Method and device for regenerating ion exchanger, and electrolytic processing apparatus

ABSTRACT

There is provided a method and device for regenerating an ion exchanger which can regenerate an ion exchanger easily and quickly, and can minimize a load upon cleaning of the regenerated ion exchanger and disposal of waste liquid. A method for regenerating a contaminated ion exchanger includes: providing a pair of a regeneration electrode and a counter electrode, a partition disposed between the electrodes, and an ion exchanger to be regenerated disposed between the counter electrode and the partition; and applying a voltage between the regeneration electrode and the counter electrode while supplying a liquid between the partition and the regeneration electrode and also supplying a liquid between the partition and the counter electrode.

TECHNICAL FIELD

[0001] The present invention relates to a method and device forregenerating an ion exchanger, and more particularly to a method anddevice for regenerating an ion exchanger which, in electrolyticprocessing for processing an electrically conductive material on thesurface of a substrate such as a semiconductor wafer or removingimpurities adhering to the substrate surface, can electrochemicallyremove a metal or other ions taken in an ion exchanger used in theelectrolytic processing, thereby regenerating the ion exchanger.

[0002] The present invention also relates to an electrolytic processingapparatus and method which is provided with the device for regeneratingan ion exchanger and which is useful for processing an electricallyconductive material on the surface of a substrate such as asemiconductor water or removing impurities adhering to the substratesurface, and to a method for such electrolytic processing.

BACKGROUND ART

[0003] In recent years, instead of using aluminum or aluminum alloys asa material for forming interconnection circuits on a substrate such as asemiconductor wafer, there is an eminent movement towards using copper(Cu) which has a low electric resistivity and high electromigrationresistance. Copper interconnects are generally formed by filling copperinto fine recesses formed in the surface of a substrate. There are knownvarious techniques for forming such copper interconnects, including CVD,sputtering, and plating. According to any such technique, a copper filmis formed in the substantially entire surface of a substrate, followedby removal of unnecessary copper by chemical mechanical polishing (CMP).

[0004]FIGS. 1A through 1C illustrate, in sequence of process steps, anexample of forming such a substrate W having copper interconnects. Asshown in FIG. 1A, an insulating film 2, such as a silicon oxide film ofSiO₂ or a film of low-k material, is deposited on a conductive layer 1 ain which electronic devices are formed, which is formed on asemiconductor base 1. A contact hole 3 and a trench 4 for interconnectsare formed in the insulating film 2 by the lithography/etchingtechnique. Thereafter, a barrier layer 5 of TaN or the like is formed onthe entire surface, and a seed layer 7 as an electric supply layer forelectroplating is formed on the barrier layer 5.

[0005] Then, as shown in FIG. 1B, copper plating is performed onto thesurface of the substrate W to fill the contact hole 3 and the trench 4with copper and, at the same time, deposit a copper film 6 on theinsulating film 2. Thereafter, the copper film 6 and the barrier layer 5on the insulating film 2 are removed by chemical mechanical polishing(CMP) so as to make the surface of the copper film 6 filled in thecontact hole 3 and the trench 4 for interconnects and the surface of theinsulating film 2 lie substantially on the same plane. Aninterconnection composed of the copper film 6 as shown in FIG. 1C isthus formed.

[0006] Components in various types of equipments have recently becomefiner and have required higher accuracy. As sub-micro manufacturingtechnology has commonly been used, the properties of materials arelargely influenced by the processing method. Under these circumstances,in such a conventional machining method that a desired portion in aworkpiece is physically destroyed and removed from the surface thereofby a tool, a large number of defects may be produced to deteriorate theproperties of the workpiece. Therefore, it becomes important to performprocessing without deteriorating the properties of the materials.

[0007] Some processing methods, such as chemical polishing, electrolyticprocessing, and electrolytic polishing, have been developed in order tosolve this problem. In contrast with the conventional physicalprocessing, these methods perform removal processing or the like throughchemical dissolution reaction. Therefore, these methods do not sufferfrom defects, such as formation of an affected layer and dislocation,due to plastic deformation, so that processing can be performed withoutdeteriorating the properties of the materials.

[0008] A processing method provided with an ion exchanger has beendeveloped as electrolytic processing. FIG. 2 illustrates the principleof this electrolytic processing. FIG. 2 shows the ionic state when anion exchanger 12 a mounted on a processing electrode 14 and an ionexchanger 12 b mounted on a feeding electrode 16 are brought intocontact with or close to a surface of a workpiece 10, while a voltage isapplied via a power source 17 between the processing electrode 14 andthe feeding electrode 16, and a liquid 18, e.g. ultrapure water, issupplied from a liquid supply section 19 between the processingelectrode 14, the feeding electrode 16 and the workpiece 10. In the caseof this electrolytic processing, water molecules 20 in the liquid 18such as ultrapure water are dissociated efficiently by using the ionexchangers 12 a, 12 b into hydroxide ions 22 and hydrogen ions 24. Thehydroxide ions 22 thus produced, for example, are carried, by theelectric field between the workpiece 10 and the processing electrode 14and by the flow of the liquid 18, to the surface of the workpiece 10opposite to the processing electrode 14 whereby the density of thehydroxide ions 22 in the vicinity of the workpiece 10 is enhanced, andthe hydroxide ions 22 are reacted with the atoms 10 a of the workpiece10. The reaction product 26 produced by this reaction is dissolved inthe liquid 18, and removed from the workpiece 10 by the flow of theliquid 18 along the surface of the workpiece 10. Removal processing ofthe surface of the workpiece 10 is thus effected.

[0009] When carrying out electrolytic processing of e.g. copper by usinge.g. a cation exchanger having cation-exchange groups, copper iscaptured by the cation-exchange groups. Progress of the consumption ofcation-exchange groups by copper makes it impossible to continue theelectrolytic processing. When electrolytic processing of copper iscarried out by using as an ion exchanger an anion exchanger havinganion-exchange groups, on the other hand, fine particles of a copperoxide are generated and the particles adhere to the surface of the ionexchanger (anion exchanger). Such particles on the ion exchanger cancontaminate the surface of a next substrate to be processed.

[0010] It is therefore considered to regenerate such consumed orcontaminated ion exchangers in order to remove the above drawbacks.Regeneration of an ion exchanger is made by exchange of an ion capturedby the ion exchanger for hydrogen ion in the case of a cation exchangeror for hydroxide ion in the case of an anion exchanger.

[0011] Ion-exchange processes using an ion exchanger are widely utilizedfor various purposes, such as purification, separation and condensation.Regeneration of an ion exchanger has conventionally been practiced byimmersing the ion exchanger in an acid solution when the exchanger is acation exchanger, or in an alkali solution when the exchanger is ananionexchanger. In the case of a cation exchanger which has captured an ionhaving an ion selectivity coefficient close to that of hydrogen ion,such as sodium ion, the ion exchanger can be regenerated in a very shorttime by immersing it in an acid solution. However, when an ionexchanger, which has captured an ion having a large ion selectivitycoefficient, is regenerated by immersing it in an acid or alkalisolution, the regeneration rate is very slow. Further, such a chemicalliquid remains at a high concentration in the regenerated ion exchanger,requiring cleaning of the ion exchanger. In addition, disposal of thechemical liquid used in the regeneration is needed.

[0012] An ion exchanger to be contacted with a workpiece is generally inthe shape of a thin film from the viewpoint of surface smoothness andflexibility. Accordingly, the ion-exchange capacity, which is a measureof processing amount, is generally small. It has therefore beenpracticed to laminate an ion exchanger having a large ion-exchangecapacity between a film-type ion exchanger and an electrode so that mostof the processing products may be taken in the laminated portion(laminated ion exchanger). Even with such a laminated ion exchanger,when the processing progresses to a certain extent, the laminatedportion cannot take in the processing products any more. Change orregeneration of the ion exchanger is therefore necessary. Change of theion exchanger is generally practiced by hand, and therefore aconsiderable time is needed for the exchange operation. When carryingout regeneration of the ion exchanger, processing must be stopped duringthe regeneration operation carried out by the conventional method, whichadversely affects the throughput of the apparatus.

DISCLOSURE OF INVENTION

[0013] The present invention has been made in view of the abovesituation in the background art. It is therefore an object of thepresent invention to provide a method and device for regenerating an ionexchanger which can regenerate an ion exchanger easily and quickly, andcan minimize a load upon cleaning of the regenerated ion exchanger anddisposal of waste liquid.

[0014] It is also an object of the present invention to provide anelectrolytic processing apparatus and method which can regenerate an ionexchanger easily and quickly without stopping processing, can minimize aload upon cleaning of the regenerated ion exchanger and can reduce theinstallation space.

[0015] In order to achieve the above object, the present inventionprovides a method for regenerating an ion exchanger for use inelectrolytic processing, comprising: providing a pair of electrodes andan ion exchanger to be regenerated disposed between the electrodes; andapplying a voltage between the electrodes while supplying a liquidtherebetween, thereby regenerating the ion exchanger.

[0016] According to this method, through an ion-exchange reactionutilizing the ion exchanger as a solid electrolyte, ions which have beentaken in the ion exchanger are moved in one direction so that the ionsare gathered in the vicinity of one electrode, and the thus gatheredions are removed from the ion exchanger by the flow of a liquid suppliedbetween the electrodes, whereby the ion exchanger can be regenerated.

[0017]FIG. 3 illustrates the principle of regeneration of an ionexchanger according to the present invention when the ion exchanger is acation exchanger. In the case of a cation exchanger, only cations canmove or migrate electrically within the cation exchanger. As shown inFIG. 3, a cation exchanger 30 a as an ion exchanger to be regeneratedis, interposed between a pair of electrodes consisting of an anode 32and a cathode 34. While supplying a liquid from a liquid supply section36 to between the anode 32 and the cathode 34, a voltage is appliedbetween the electrodes from a regeneration power source 38. Dissolvedions M⁺ of a to-be-processed material, which have been taken in thecation exchanger (ion exchanger to be regenerated) 30 a duringprocessing of the material, and ions M⁺ of a solid product, derivingfrom the to-be-processed material, deposited on the surface of theprocessing electrode then move from the anode 32 side to the cathode 34side. The ions M⁺ thus gathered on the cathode 34 side are precipitatedon the cathode 34 by plating, but part of the ions are removed from thecation exchanger (ion exchanger to be regenerated) 30 a by the flow of aliquid.

[0018] In the case of an anion exchanger, only anions can moveelectrically within the anion exchanger. Thus, in regeneration of ananion exchanger, anions in the anion exchanger can be gathered on theanode side and removed by the same operation as described above.

[0019] The liquid is, preferably, ultrapure water, pure water, a liquidhaving an electric conductivity of not more than 500 μS/cm, or anelectrolytic solution.

[0020] Ultrapure water is generally a water having an electricconductivity (referring herein to that at 25° C., 1 atm) of not morethan 0.1 μS/cm. Pure water is generally a water having an electricconductivity of not more than 10 μS/cm. The use of pure water inelectrolytic processing enables a clean processing without leavingimpurities on the processed surface of a workpiece, whereby a cleaningstep after the electrolytic processing can be simplified. Specifically,one or two-stages of cleaning may suffice after the electrolyticprocessing.

[0021] It is also possible to use a liquid obtained by adding anadditive, such as a surfactant, to pure water or ultrapure water, andhaving an electric conductivity of not more than 500 μS/cm, preferablynot more than 50 μS/cm, more preferably not more than 0.1 μS/cm(resistivity of not less than 10 MΩ·cm). The local concentration ofreactant ions can be prevented by allowing the additive, which plays arole to prevent local concentration of ions (e.g. hydroxide ions), toexist between a workpiece and an ion exchanger.

[0022] An aqueous solution of a neutral salt such as NaCl or Na₂SO₄, anacid such as HCl or H₂SO₄, or an alkali such as ammonia may be used asthe electrolytic solution, and may be properly selected according to theproperties of a workpiece.

[0023] It is preferred that an ion exchanger for regeneration bedisposed between the ion exchanger to be regenerated and at least one ofthe electrodes. This can prevent ions, flowing in one direction withinthe ion exchanger to be generated, from adhering to the electrode, thuspreventing a solid matter adhering to the electrode from contaminatingthe regenerated ion exchanger.

[0024] The ion exchanger for regeneration preferably has an ion-exchangegroup of the same polarity as the ion-exchange group of the ionexchanger to be regenerated. This allows ions to move from one ionexchanger to the other ion exchanger.

[0025] The electrode disposed on the side of the ion exchanger to beregenerated may be an anode when the ion exchanger to be regenerated andthe ion exchanger for regeneration are cation exchangers, and a cathodewhen the both ion exchangers are anion exchangers.

[0026] When regenerating a cation exchanger which uses acation-exchanger group as an ion-exchanger group, the cation exchanger(ion exchanger to be regenerated) is positioned on the anode side of thepair of electrodes, and the ion exchanger for regeneration is positionedon the cathode side. Thus, as shown in FIG. 4, the cation exchanger 30 ato be regenerated and the cation exchanger 40 for regeneration areinterposed between the pair of electrodes consisting of the anode 32 andthe cathode 34 so that the anode 32 is on the side of the cationexchanger (ion exchanger to be regenerated) 30 a. While supplying aliquid from the liquid supply section 36 to between the anode 32 and thecathode 34, a voltage is applied from the regeneration power source 38.Ions M⁺ in the cation exchanger (ion exchanger to be regenerated) 30 athen move to the side of the ion exchanger 40 for regeneration. Thecation exchanger 30 a is thus regenerated.

[0027] On the other hand, when regenerating an anion exchanger whichuses an anion-exchange group as an ion-exchange group, the anionexchanger (ion exchanger to be regenerated) is positioned on the cathodeside of the pair of electrodes, and the ion exchanger for regenerationis positioned on the anode side. Thus, as shown in FIG. 5, the anionexchanger 30 b to be regenerated and the cation exchanger 40 forregeneration are interposed between the pair of electrodes consisting ofthe anode 32 and the cathode 34 so that the cathode 34 is on the side ofthe anion exchanger (ion exchanger to be regenerated) 30 b. Whilesupplying a liquid from the liquid supply section 36 to between theanode 32 and the cathode 34, a voltage is applied from the regenerationpower source 38. Ions X⁻ in the anion exchanger (ion exchanger to beregenerated) 30 b then move to the side of the ion exchanger 40 forregeneration. The anion exchanger 30 b is thus regenerated.

[0028] The present invention provides a device for regenerating an ionexchanger that is disposed on an electrode for use in electrolyticprocessing, comprising: a regeneration section including a regenerationelectrode; a regeneration power source for applying a voltage betweenthe electrode and the regeneration electrode; and a liquid supplysection for supplying a liquid between the electrode and theregeneration electrode; wherein the ion exchanger to be regenerated isdisposed between the electrode and the regeneration electrode.

[0029] According to the device, an ion exchanger to be regenerated ispositioned between the electrode plate and the regeneration electrode,and a voltage is applied between the electrode plate and theregeneration electrode while supplying a liquid therebetween, wherebythe ion exchanger can be regenerated.

[0030] It is preferred that an ion exchanger for regeneration bedisposed between the ion exchanger to be regenerated and theregeneration electrode.

[0031] With the ion exchanger to be regenerated and the ion exchangerfor regeneration thus facing each other, a liquid is supplied and avoltage is applied between the electrode plate and the regenerationelectrode to regenerate the former ion exchanger.

[0032] It is preferred that at least one of the ion exchanger to beregenerated and the ion exchanger for regeneration be a laminateconfigured by a plurality of ion-exchange materials.

[0033] When the ion exchanger to be regenerated is a laminate of aplurality of ion-exchange materials, the plurality of ion-exchangematerials (ion exchanger to be regenerated) can be regeneratedsimultaneously. When the ion exchanger for regeneration is configured bya lamination of plurality of ion-exchange materials, the substantialion-exchanger capacity of the ion exchanger for regeneration isincreased, and more ion exchanger (ion exchanger to be regenerated) canbe regenerated continuously.

[0034] A monitor for monitoring the electrolysis current and time and/orthe quantity of electricity when the voltage is applied between theelectrode and the regeneration electrode may be provided.

[0035] The regeneration amount of an ion exchanger is governed by theproduct of the electrolysis current and the electrolysis time, i.e. thequantity of electricity. Accordingly, by monitoring at least one of theelectrolysis current and time, and/or the quantity of electricity by themonitor, it becomes possible to control the regeneration amount anddetect the end point of regeneration.

[0036] The present invention provides another method for regeneratingcontaminated ion exchanger, comprising: providing a regenerationelectrode and a counter electrode, a partition disposed between theregeneration electrode and the counter electrode, and an ion exchangerto be regenerated disposed between the counter electrode and thepartition; and applying a voltage between the regeneration electrode andthe counter electrode while supplying a liquid between the partition andthe regeneration electrode and also supplying a liquid between thepartition and the counter electrode.

[0037] According to this method, through an ion-exchange reactionutilizing the ion exchanger as a solid electrolyte, ions taken in theion exchanger are moved toward the regeneration electrode and passedthrough the partition, and the ions which have passed through thepartition are discharged out of the system by the flow of a liquidsupplied between the partition and the regeneration electrode, wherebythe ion exchanger can be regenerated.

[0038] The partition preferably comprises an ion exchanger. It isdesired that the partition does not hinder the migration therethrough ofimpurity ions from the ion exchanger to be regenerated and inhibitpermeation therethrough of the liquid (including ions in the liquid)flowing between the partition and the regeneration electrode into theside of the ion exchanger to be regenerated. In this regard, ionexchangers permit selective permeation therethrough of cations oranions. A suitable ion exchanger as a partition can be selected.Further, a film-type ion exchanger as a partition can prevent intrusionof the liquid flowing between the partition and the regenerationelectrode into the to-be-regenerated ion exchanger side. Thus, asuitably selected film-type ion exchanger can meet the aboverequirements for the partition.

[0039] In a preferred embodiment, the partition may be a cationexchanger when the ion exchanger to be regenerated is a cationexchanger, and an anion exchanger when the ion exchanger to beregenerated is an anion exchanger. According to this embodiment, thepartition (ion exchanger) has an ion-exchange group of the same polarityas the ion-exchange group of the ion exchanger to be regenerated. Such apartition can permit permeation therethrough of only those ions ascoming from the ion exchanger to be regenerated and inhibit migrationtherethrough of ions in the liquid flowing between the partition and theregeneration electrode into the to-be-regenerated ion exchanger side.

[0040] The regeneration electrode may be a cathode when the ionexchanger to be regenerated is a cation exchanger, and an anode when theion exchanger to be regenerated is an anion exchanger.

[0041] In the case of a cation exchanger, only cations can move ormigrate electrically within the cation exchanger. When regenerating acation exchanger, as shown in FIG. 6, a pair of a regeneration electrode43 and a counter electrode 44, a partition 42 disposed between theelectrodes, and a cation exchanger 41 as an ion exchanger to beregenerated, disposed between the counter electrode 44 and the partition42, are provided. A liquid A is supplied from a first liquid supplysection 45 to between the partition 42 and the regeneration electrode 43and a liquid B is supplied from a second liquid supply section 46 tobetween the partition 42 and the counter electrode 44 and, at the sametime, a voltage is applied from a regeneration power source 47 tobetween the regeneration electrode 43 as a cathode and the counterelectrode 44 as an anode. Dissolved ions M⁺ of a to-be-processedmaterial, which have been taken in the cation exchanger (ion exchangerto be regenerated) 41 during processing of the material, then move fromthe counter electrode (anode) 44 side toward the regeneration electrode(cathode) 43 side and pass through the partition 42. The ions M⁺ whichhave passed through the partition 42 are discharged out of the system bythe flow of liquid A supplied between the partition 42 and theregeneration electrode 43. The cation exchanger 41 is thus regenerated.

[0042] In the case of an anion exchanger, on the other hand, only anionscan move or migrate electrically within the anion exchanger. Whenregenerating an anion exchanger, as shown in FIG. 7, a pair of aregeneration electrode 43 and a counter electrode 44, a partition 42disposed between the electrodes, and an anion exchanger 41 a as an ionexchanger to be regenerated, disposed between the counter electrode 44and the partition 42, are provided. A liquid A is supplied from a firstliquid supply section 45 to between the partition 42 and theregeneration electrode 43 and a liquid B is supplied from a secondliquid supply section 46 to between the partition 42 and the counterelectrode 44 and, at the same time, a voltage is applied from aregeneration power source 47 to between the regeneration electrode.43 asan anode and the counter electrode 44 as a cathode. Dissolved ions X⁻ inthe anion exchanger (ion exchanger to be regenerated) 41 a then movefrom the counter electrode (cathode) 44 side toward the regenerationelectrode (anode) 43 side and pass through the partition 42. The ions X⁻which have passed through the partition 42 are discharged out of thesystem by the flow of liquid A supplied between the partition 42 and theregeneration electrode 43. The anion exchanger 41 a is thus regenerated.

[0043] The liquid supplied between the partition and the counterelectrode is preferably ultrapure water, pure water or a liquid havingan electric conductivity of not more than 500 μS/cm.

[0044] The liquid supplied between the partition and the regenerationelectrode is preferably a liquid having an electric conductivity of notless than 50 μS/cm which does not form a hardly soluble or insolublecompound through a reaction with an ion which is removed from the ionexchanger to be regenerated.

[0045] Such a liquid having an electric conductivity of not less than 50μS/cm, because of its low electric resistance, can reduce the powerconsumption in the regeneration system. Further, the liquid does notform an insoluble compound (by-product) through a reaction with animpurity ion. In this regard, an insoluble compound, if formed, willadhere to the partition whereby the electric resistance between theregeneration electrode and the counter electrode will be changed, makingit difficult to control the electrolysis current. Such a problem canthus be prevented. A suitable liquid may be chosen depending upon thekind of the impurity ion to be discharged. For example, whenregenerating an ion exchanger that was used in electrolytic polishing ofcopper, sulfuric acid with a concentration of 1 wt % or higher may beemployed.

[0046] The present invention provides another device for regenerating anion exchanger, comprising: a regeneration electrode and a counterelectrode disposed opposite to each other; a partition disposed betweenthe regeneration electrode and the counter electrode; a power source forapplying a voltage between the regeneration electrode and the counterelectrode; and a liquid supply section for supplying a liquid betweenthe partition and the regeneration electrode and/or between thepartition and the counter electrode; wherein an ion exchanger to beregenerated is disposed between the partition and the counter electrode.

[0047] According to this device, an ion exchanger to be regenerated isdisposed opposite to the regeneration electrode with the partition beinginterposed therebetween, and a voltage is applied between theregeneration electrode and the counter electrode while supplying aliquid between the partition and the regeneration electrode and alsosupplying a liquid between the partition and the counter electrode,whereby the ion exchanger can be regenerated.

[0048] The present invention provides an electrolytic processingapparatus, comprising: a processing electrode which can come close to orinto contact with a workpiece; a feeding electrode for feedingelectricity to the workpiece; an ion exchanger provided on a workpieceside surface of at least one of the processing electrode and the feedingelectrode; a regeneration section provided between the ion exchanger andthe at least one of the processing electrode and the feeding electrode,provided with the ion exchanger; a processing power source for applyinga processing voltage between the processing electrode and the feedingelectrode; and a processing liquid supply section for supplying aprocessing liquid for electrolytic processing to between the workpieceand the at least one of the processing electrode and the feedingelectrode, in which the ion exchanger is present.

[0049] According to this apparatus, the processing electrode is broughtclose to or into contact with a workpiece while feeding electricity fromthe feeding electrode to the workpiece, and a processing liquid forelectrolytic processing is supplied to between the workpiece and atleast one of the processing electrode and the feeding electrode, inwhich the ion exchanger is present, while a processing voltage isapplied between the processing electrode and the feeding electrode. Bythe above operation, electrolytic processing of the workpiece by theprocessing electrode and regeneration of the ion exchanger by theregeneration section can be carried out simultaneously.

[0050] The regeneration section preferably comprises a partitiondisposed close to or in contact with the ion exchanger, a dischargeportion formed between the partition and at least one of the processingelectrode and the feeding electrode, and a discharging liquid supplysection for supplying a discharging liquid to the discharge portion, fordischarging contaminants contained in the ion exchanger.

[0051] According to the regeneration section, through an ion-exchangereaction utilizing the ion exchanger as a solid electrolyte, impurityions, such as ionic processing products, which are being taken in theion exchanger during electrolytic processing, are moved toward theprocessing electrode or the feeding electrode and passed through thepartition, and the impurity ions that have passed through the partitionare discharged out of the system by the flow of the discharging liquidsupplied to the discharge portion, whereby the ion exchanger can beregenerated.

[0052] In the case of a cation exchanger, only cations can move ormigrate electrically within the cation exchanger. When the processingelectrode, for example, is made a cathode, a cation exchanger (ionexchange) is mounted so that it may cover the surface of the processingelectrode. If it is intended to regenerate the cation exchanger, asshown in FIG. 8 on the right side, a regeneration section 234 a isprovided between a cation exchanger 230 a and a processing electrode(cathode) 232. In the case of an anion exchanger, on the other hand,only anions can move electrically within the anion exchanger. When thefeeding electrode, for example, is made an anode, an anion exchanger(ion exchanger) is mounted so that it may cover the surface of thefeeding electrode. If it is intended to regenerate the anion exchanger,as shown in FIG. 8 on the left side, a regeneration section 234 b isprovided between an anion exchanger 230 b and a feeding electrode(anode) 236.

[0053] The regeneration sections 234 a, 234 b each comprise a partition238 disposed closed to or in contact with the ion exchanger (cationexchanger 230 a or anion exchanger 230 b), a discharge portion 240formed between the processing electrode 232 or the feeding electrode 236and the partition 238, and a discharging liquid supply section 242 forsupplying to the discharge portion 240 a discharging liquid A fordischarging contaminants. When a workpiece, such as a substrate W, isclose to or in contact with the ion exchanger (cation exchanger 230 aand/or anion exchanger 230 b), the discharging A for dischargingcontaminants is supplied from the discharging liquid supply section 242to the discharge portion 240 and a processing liquid B for electrolyticprocessing is supplied from an electrolytic processing liquid supplysection 244 to between the partition 238 and the ion exchanger (cationexchanger 230 a and/or anion exchanger 230 b), while a voltage isapplied from a processing power source 246 to between the processingelectrode 232 as a cathode and the feeding electrode 236 as an anode,thereby carrying out electrolytic processing.

[0054] During the electrolytic processing, in the cation exchanger 230a, ions such as dissolved ions M⁺ of a to-be-processed material, whichare being taken in the cation exchanger, move toward the processingelectrode (cathode) 232 and pass through the partition 238. The ions M⁺that have passed the partition 238 are discharged out of the system bythe flow of the discharging liquid A supplied between the partition 238and the processing electrode 232. The cation exchanger 230 a is thusregenerated. When a cation exchanger is used as the partition 238, thepartition (cation exchanger) 238 can permit permeation therethrough ofonly ions M⁺ coming from the cation exchanger 230 a. In the anionexchanger 230 b, on the other hand, ions X⁻ in the anion exchanger 230 bmove toward the feeding electrode (anode) 236 and pass through thepartition 238. The ions X⁻ that have passed the partition 238 aredischarged out of the system by the flow of the discharging liquid Asupplied between the partition 238 and the feeding electrode 236. Theanion exchanger 230 b is thus regenerated. When an anion exchanger isused as the partition 238, the partition (anion exchanger) 238 canpermit permeation therethrough of only ions X⁻ coming from the anionexchanger 230 b.

[0055] Though a single liquid A is used as the liquid for dischargingcontaminants in this embodiment, it is also possible to use differentliquids according to the types of impurity ions discharged from the ionexchangers.

[0056] The discharging liquid is preferably a liquid having an electricconductivity of not less than 50 μS/cm which does not form a hardlysoluble or insoluble compound through a reaction with an ion which isremoved from the ion exchanger provided on a workpiece side surface ofat least one of the processing electrode and the feeding electrode.

[0057] The present invention provides another electrolytic processingapparatus comprising: a processing electrode which can come close to orinto contact with a workpiece; a feeding electrode for feedingelectricity to the workpiece; an ion exchanger provided on a workpieceside surface of at least one of the processing electrode and the feedingelectrode; a regeneration section including a regeneration electrode anda discharge portion for flowing a discharging liquid therethrough, thedischarge portion being formed between the regeneration electrode andthe at least one of the processing electrode and the feeding electrode,provided with the ion exchanger; a processing power source for applyinga processing voltage between the processing electrode and the feedingelectrode; and a processing liquid supply section for supplying aprocessing liquid for electrolytic processing to between the workpieceand the at least one of the processing electrode and the feedingelectrode, in which the ion exchanger is present.

[0058] In case as shown in FIG. 9, if it is intended to regenerate theion exchanger 230 a by utilizing only the electrode 248 both as aprocessing electrode and a regeneration electrode, especially when theion exchanger 230 a is thick, the amount of processing products taken inby the ion exchanger during processing can be large and the processingmay be continued for a long time. On the other hand, however, theelectric field is likely to vary due to deposition of the processingproducts or impurities, accumulation of gas bubbles, etc. Thus, theelectric resistances of internal micro portions of the ion exchanger 230a will change to thereby change the current values. This affects theefficiency of ion migration and makes it difficult to effect a uniformregeneration of the ion exchanger 230 a. In order to obviate suchdrawbacks, a processing electrode 232 may be provided independently asshown in FIG. 9, and the electrode 248, positioned below the processingelectrode 232, may be utilized as an electrode exclusively forregeneration (regeneration electrode). This suppresses the variation ofelectric field and enables uniform removal of ionic processing products(impurity ions), etc. accumulated within the ion exchanger 230 a.

[0059] More specifically, on the opposite side of the processingelectrode 232 from the ion exchanger (cation exchanger) 230 a isprovided a regeneration section 234 c including the regenerationelectrode 248 and a discharge portion 240 a, formed between theregeneration electrode 248 and the processing electrode 232, for flowinga discharging liquid (liquid A) therethrough. A regeneration voltage isapplied from a regeneration power source 249 to between the processingelectrode 232 and the regeneration electrode 248, thereby forciblypassing an electric current therebetween. Regeneration of the ionexchanger 230 a can be effected in this way. A processing power source,because of its need for a CC (constant current) or CV (constant voltage)control, is generally expensive. A regeneration power source, on theother hand, needs no such control, and therefore a less expensiveelectrode can be utilized as the regeneration electrode 249.

[0060] In a preferred embodiment, the electrolytic processing apparatusfurther comprises a partition between the ion exchanger and the at leastone of the processing electrode and the feeding electrode, provided withthe ion exchanger, and/or between the regeneration electrode and the oneof the processing electrode and the feeding electrode. According to thisembodiment, ionic processing products (impurity ions), etc. taken in theion exchanger are moved toward the processing electrode or the feedingelectrode and passed through the partition. The impurity ions that havepassed the partition are taken in the discharging liquid supplied to thedischarging portion and discharged out of the system by the flow of thedischarging liquid. The ion exchanger can thus be purified (regenerated)in a continuous manner.

[0061] The partition is preferably provided on the both sides of the atleast one of the processing electrode and the feeding electrode,provided with the ion exchanger. For example, two partitions maybeprovided on the both surfaces of the processing electrode. In this case,even when the partitions undergo pressure differences due to thepressing force applied to a workpiece, the pressure of a processingliquid and the pressure of a discharging liquid, the partition can beused for a long time without deformation or breakage owing to thesupport by the electrode. Should one of the partitions be broken forsome reason, the remaining one can prevent the discharging liquid fromflowing out to the processing liquid side, and therefore prevent thedischarging liquid (usually an electrolytic solution) from contactingthe workpiece.

[0062] Preferably, the at least one of the processing electrode and thefeeding electrode, provided with the ion exchanger, is in contact withthe partition and is supported and fixed on a support. According to thisembodiment, positioning and fixing of the partition can be madeautomatically by supporting and fixing the processing electrode on asupport. This eliminates the need to separately provide a structure forholding the partition.

[0063] Preferably, the at least one of the processing electrode and thefeeding electrode, provided with the ion exchanger, has a through-holefor passing therethrough the discharging liquid or the processingliquid. Ionic processing products (impurity ions), etc. coming from theion exchanger pass through the through-hole provided in e.g. theprocessing electrode and reach the discharge portion. Such athrough-hole may be provided e.g. by using a mesh electrode.

[0064] It is preferred that the electrolytic processing apparatusfurther comprise an intermediate electrode between the workpiece and theat least one of the processing electrode and the feeding electrode,provided with the ion exchanger. The provision of the intermediateelectrode can change the electric potential stepwise, and can alsoequalize and stabilize the electric field.

[0065] The intermediate electrode and the one of the processingelectrode and the feeding electrode, provided with the ion exchanger arepreferably connected to an intermediate power source. This can changethe voltage stepwise, and can also equalize and stabilize the electricfield. It is desired that the voltage applied from the intermediatepower source be smaller than the overall voltage (voltage forregeneration).

[0066] The intermediate electrode may be a floating electrode that isnot connected to a power source. Even a floating electrode can changethe voltage stepwise and stabilize the electric field.

[0067] Preferably, the intermediate electrode has a through-hole forpassing therethrough the discharging liquid or the processing liquid.Ionic processing products (impurity ions) etc. coming from the ionexchanger pass through the through-hole(s) provided in the intermediateelectrode and reach the discharge portion. Such a through-hole may beprovided e.g. by using a mesh electrode.

[0068] The intermediate electrode may be laminated with an ion exchangeror a partition. By thus increasing the number of the intermediateelectrode, it becomes possible to change stepwise the electric potentialmore uniformly.

[0069] Preferably, the discharge portion is provided with a stirringmeans for forcibly stirring the discharging liquid in the dischargeportion. Forcible stirring of the discharging liquid in the dischargingportion can prevent gas bubbles (hydrogen gas bubbles in removalprocessing of copper) generated in the surface of the processingelectrode upon electrolytic processing from adhering to and growing onthe partition and the electrode, thus preventing grown gas bubbles fromimpeding the formation of a uniform electric field. Further, theforcible stirring can lower the ion concentration of to-be-dischargedions in the vicinity of the partition, thus preventing the ions fromimpeding the ion-exchange reaction.

[0070] It is preferred that the electrolytic processing apparatusfurther comprise a deaerator for deaerating the discharging liquid. Asdescribed above, gas bubbles are generated in electrolytic processing.This increases the concentration of dissolved gas in the dischargingliquid which has flowed into and is discharged out of the dischargeportion. The provision of a deaerator, which deaerates the dischargingliquid that has flowed out of the discharge portion, makes it possibleto reuse the discharging liquid. As the deaerator, it is possible to usee.g. a deaerating film-type deaerating chamber, with which deaeration iscarried out as follows: A liquid to-be-treated (discharging liquid) isintroduced into a hollow non-liquid-permeable thread film, and theexternal pressure of the film is reduce to deaerate the liquid. Thedischarging liquid may be reused either batchwise or in a circulatorymanner.

[0071] The present invention provides an electrolytic processing method,comprising: providing a processing electrode, a feeding electrode, anion exchanger provided on a workpiece side surface of at least one ofthe processing electrode and the feeding electrode, and a regenerationsection formed between the ion exchanger and the at least one of theprocessing electrode and the feeding electrode; allowing the processingelectrode to be closed to or in contact with the workpiece while feedingelectricity from the feeding electrode to the workpiece; supplying aprocessing liquid for electrolytic processing to between the workpieceand the at least one of the processing electrode and the feedingelectrode, in which the ion exchanger is present; and applying aprocessing voltage between the processing electrode and the feedingelectrode, thereby carrying out electrolytic processing of the workpieceby the processing electrode and regeneration of the ion exchanger by theregeneration section simultaneously.

[0072] The present invention provides still another electrolyticprocessing apparatus, comprising: a processing electrode which can comeclose to or into contact with a workpiece; a feeding electrode forfeeding electricity to the workpiece; an ion exchanger provided on aworkpiece side surface of at least one of the processing electrode andthe feeding electrode; a discharging liquid flow passage, formed betweenthe ion exchanger and the at least one of the processing electrode andthe feeding electrode, provided with the ion exchanger, for flowingtherethrough a discharging liquid for discharging contaminants containedin the ion exchanger; a processing power-source for applying aprocessing voltage between the processing electrode and the feedingelectrode; and a processing liquid supply section for supplying aprocessing liquid for electrolytic processing to between the workpieceand the at least one of the processing electrode and the feedingelectrode, in which the ion exchanger is present.

[0073] According to the electrolytic processing apparatus, processingproducts as dissolved ions (impurity ions) are taken in the ionexchanger at the early stage of electrolytic processing, and when theion-exchange capacity of the ion exchanger reaches its limit, the ionicprocessing products (impurity ions) can be taken in the dischargingliquid flowing through the discharging liquid flow passage formedbetween the ion exchanger and the electrode (processing electrode orfeeding electrode), whereby the ion exchanger can be regenerated. Theapparatus can thus eliminate or at least lessen the exchange of theexpendable member.

[0074] Preferably, a support for supporting the ion exchanger in a flatstate is provided in the discharging liquid flow passage. The provisionof such a support makes it possible to use an ion exchange in the formof a thin film, and allow the ion exchanger to contact a workpieceflexibly. The flexibility is required to respond to variations of theto-be-processed surface of a workpiece due the size of the workpiece,the relative movement between the workpiece and the ion exchanger, etc.

[0075] The ion-exchanger is preferably a multi-layer laminate of two ormore layers including a front surface layer composed of an ion exchangerin the form of a film and an intermediate or back surface layer composedof an elastic ion exchanger having a large ion-exchange capacity. Such alaminate, though the ion-exchange capacity of the surface layer ionexchanger may be small, can have an increased total ion-exchangecapacity due to the presence of the intermediate or back surface ionexchanger. Moreover, because of the elasticity, the laminate can beprevented the workpiece from being damaged when an excessive pressure isapplied thereto in electrolytic processing.

[0076] It is preferred that the electrolytic processing apparatusfurther comprise a discharging liquid regeneration section forregenerating the discharging liquid which has flowed through thedischarging liquid flow passage and flowed out of the flow passage. Thismakes it possible to reuse the discharging liquid, thereby lowering therunning cost of the apparatus.

[0077] The discharging liquid regeneration section is preferablyprovided with a liquid regeneration electrode which is electricallyseparated from the discharging liquid to be regenerated. The use of sucha liquid regeneration electrode can carry out regeneration of thedischarging liquid efficiently while preventing a short circuit.

[0078] Preferably, the discharging liquid regeneration section isprovided in a circulation line connecting in the inlet and the outlet ofthe discharging liquid passage, and the circulation line is providedwith a deaerator. This allows the discharging liquid to circulate duringprocessing.

[0079] The present invention provides still another electrolyticprocessing apparatus comprising: a processing electrode which can comeclose to or into contact with a workpiece; a feeding electrode forfeeding electricity to the workpiece; an ion exchanger provided on aworkpiece side surface of at least one of the processing electrode andthe feeding electrode; a discharging liquid flow passage, formed betweenthe ion exchanger and the at least one of the processing electrode andthe feeding electrode, provided with the ion exchanger, for flowingtherethrough a discharging liquid containing an ion-exchange group fordischarging contaminants; a processing power source for applying aprocessing voltage between the processing electrode and the feedingelectrode; and a processing liquid supply section for supplying aprocessing liquid for electrolytic processing to between the workpieceand the at least one of the processing electrode and the feedingelectrode, in which the ion exchanger is present.

[0080] Examples of the discharging liquid containing an ion-exchangegroup may include an ion exchanger which itself has liquidity and aliquid obtained by pulverizing an ion exchanger having a largeion-exchange capacity, and mixing the pulverized product with a liquidsuch as pure water.

[0081] Further, the present invention provides another electrolyticprocessing method comprising: providing a processing electrode, afeeding electrode and an ion exchanger provided on a workpiece sidesurface of at least one of the processing electrode and the feedingelectrode; allowing the processing electrode to be close to or incontact with a workpiece while feeding electricity from the feedingelectrode to the workpiece; and applying a processing voltage betweenthe processing electrode and the feeding electrode while supplying adischarging liquid containing an ion-exchange group for dischargingcontaminants into a discharging liquid flow passage formed between theion exchanger and the at least one of the processing electrode and thefeeding electrode, provided with the ion exchanger, and also supplying aprocessing liquid for electric processing to between the workpiece andthe at least one of the processing electrode and the feeding electrode,in which the ion exchanger is present, thereby carrying out processingof the workpiece.

[0082] The above and other objects, features, and advantages of thepresent invention will be apparent from the following description whentaken in conjunction with the accompanying drawings which illustratespreferred embodiments of the present invention by way of example.

BRIEF DESCRIPTION OF DRAWINGS

[0083]FIGS. 1A through 1C are diagrams illustrating, in sequence ofprocess steps, an example of the formation of copper interconnects;

[0084]FIG. 2 is a diagram illustrating the principle of electrolyticprocessing as carried out by using an ion exchanger;

[0085]FIG. 3 is a diagram illustrating the principle of regeneration ofan ion exchanger as carried out by disposing the ion exchanger to beregenerated between a pair of electrodes according to the presentinvention;

[0086]FIG. 4 is a diagram illustrating the principle of regeneration ofan ion exchanger as carried out by disposing the ion exchanger (anionexchanger) to be regenerated and an ion exchanger for regenerationbetween a pair of electrodes according to the present invention;

[0087]FIG. 5 is a diagram illustrating the principle of regeneration ofan ion exchanger as carried out by disposing the ion exchanger (cationexchanger) to be regenerated and an ion exchanger for regenerationbetween a pair of electrodes according to the present invention;

[0088]FIG. 6 is a diagram illustrating the principle of regeneration ofa cation exchanger as carried out according to the present invention;

[0089]FIG. 7 is a diagram illustrating the principle of regeneration ofan anion exchanger as carried out according to the present invention;

[0090]FIG. 8 is a diagram illustrating the principle of electrolyticprocessing/regeneration as carried out by an ion regeneration deviceaccording to the present invention;

[0091]FIG. 9 is a diagram illustrating the principle of electrolyticprocessing/regeneration as carried out by another ion regenerationdevice according to the present invention;

[0092]FIG. 10 is a cross-sectional view of an electrolytic processingapparatus provided with an ion exchanger regeneration device accordingto an embodiment of the present invention, showing the state of theapparatus upon electrolytic processing;

[0093]FIG. 11 is a plan view of FIG. 10;

[0094]FIG. 12 is a cross-sectional view of an electrolytic processingapparatus provided with an ion exchanger regeneration device accordingto an embodiment of the present invention, showing the state of theapparatus upon regeneration of an ion exchanger;

[0095]FIG. 13 is a plan view of FIG. 12;

[0096]FIG. 14 is a diagram showing the layout of a substrate processingapparatus provided with the electrolytic processing apparatus shown inFIGS. 10 through 13;

[0097]FIG. 15 is a cross-sectional view of an electrolytic processingapparatus provided with an ion exchanger regeneration device accordingto another embodiment of the present invention, in which the solid linesshow the apparatus upon electrolytic processing and the imaginary linesshow the apparatus upon regeneration;

[0098]FIG. 16 is a plan view of FIG. 15;

[0099]FIG. 17 is a cross-sectional view of the main part of anelectrolytic processing apparatus provided with an ion exchangerregeneration device according to still another embodiment of the presentinvention;

[0100]FIG. 18 is a cross-sectional view of an electrolytic processingapparatus provided with an ion exchanger regeneration device accordingto still another embodiment of the present invention, showing the stateof the apparatus upon electrolytic processing;

[0101]FIG. 19 is a cross-sectional view of an electrolytic processingapparatus provided with an ion exchanger regeneration device accordingto still another embodiment of the present invention, showing the stateof the apparatus upon regeneration of an ion exchanger;

[0102]FIG. 20 is a cross-sectional view of an electrolytic processingapparatus according to still another embodiment of the presentinvention, showing the state of the apparatus upon electrolyticprocessing;

[0103]FIG. 21 is an enlarged view of the main part of the electrolyticprocessing apparatus shown in FIG. 20;

[0104]FIG. 22 is a cross-sectional view of an electrolytic processingapparatus according to still another embodiment of the presentinvention, showing the state of the apparatus upon electrolyticprocessing;

[0105]FIG. 23 is an enlarged sectional view of the processing electrodeportion shown in FIG. 22;

[0106]FIGS. 24A and 24B are enlarged sectional views showing otherprocessing electrode portions;

[0107]FIG. 25 is a cross-sectional view of another regeneration sectionaccording to the present invention;

[0108]FIG. 26 is a system diagram illustrating a circulation system of adischarging liquid, provided with the regeneration section of FIG. 25;

[0109]FIG. 27 is a plan view of an electrolytic processing apparatusaccording to still another embodiment of the present invention;

[0110]FIG. 28 is a vertical sectional view of the electrolyticprocessing apparatus of FIG. 27;

[0111]FIG. 29A is a plan view of a rotation-prevention mechanismprovided in the electrolytic processing apparatus of FIG. 27, and FIG.29B is a sectional view taken along the line A-A of FIG. 29A;

[0112]FIG. 30A is a perspective view of an ion exchanger in theregeneration section of the electrolytic processing apparatus of FIGS.27 and 28, FIG. 30B is a perspective view of an electrode (processingelectrode) in the same regeneration section, and FIG. 30C is aperspective view showing the state of the ion exchanger and theelectrode when the ion exchanger is mounted on the electrode;

[0113]FIG. 31 is a system diagram illustrating a distribution system ofa discharging liquid, provided with the regeneration section shown inFIGS. 30A through 30C;

[0114]FIG. 32 is a system diagram illustrating an circulation system ofa discharging liquid, provided with the regeneration section shown inFIGS. 30A through 30C;

[0115]FIG. 33 is a cross-sectional view of an electrode section havingstill another regeneration section according to the present invention;

[0116]FIG. 34 is an enlarged view of the main part of the regenerationsystem of FIG. 33;

[0117]FIG. 35 is an enlarged view of the main part of a variation of theregeneration section shown in FIGS. 33 and 34;

[0118]FIG. 36 is a plan view of an electrolytic processing apparatusaccording to still another embodiment of the present invention;

[0119]FIG. 37 is a right side view of the electrolytic processingapparatus of FIG. 36; and

[0120]FIG. 38 is an enlarged view of the main part of the electrolyticprocessing apparatus of FIG. 36.

BEST MODE FOR CARRYING OUT THE INVENTION

[0121] Preferred embodiments of the present invention will now bedescribed with reference to the drawings. Though the below-describedembodiments refer to application to electrolytic processing apparatuses(electrolytic polishing apparatuses) which use a substrate as aworkpiece to be processed and remove (polish) copper formed on thesurface of the substrate, the present invention is of course applicableto the other workpiece, and to other electrolytic process.

[0122]FIGS. 10 through 13 show an electrolytic processing apparatus 48 ahaving a regeneration device of an ion exchanger according to a firstembodiment of the present invention. This electrolytic processingapparatus 48 a includes a substrate holder 52, supported at the free endof a pivot arm 50 that can pivot horizontally, for attracting andholding the substrate W with its front surface facing downward(so-called “face-down” manner), a disc-shaped electrode section 60 madeof an insulating material and positioned beneath the substrate holder52, and a regeneration section 64, supported at the free end of a pivotarm 62 that can pivot horizontally, for regenerating the ion exchanger58. The electrode section 60 has, embedded therein, fan-shapedprocessing electrodes 54 and feeding electrodes 56 that are disposedalternately with their surfaces (upper faces) exposed. The film-like ionexchanger 58 is mounted on the upper surface of the electrode section 60so as to cover the surfaces of the processing electrodes 54 and thefeeding electrodes 56. This embodiment uses, merely as an example of theelectrode section 60 having the processing electrodes 54 and the feedingelectrodes 56, such one that has a diameter a little longer than that ofthe substrate W held by the substrate holder 52 so that the entiresurface of the substrate W may undergo electrolytic processing by makinga scroll movement of the electrode section 60.

[0123] The ion exchanger 58 may be a nonwoven fabric which has ananion-exchange group or a cation-exchange group. A cation exchangerpreferably carries a strongly acidic cation-exchange group (sulfonicacid group); however, a cation exchanger carrying a weakly acidiccation-exchange group (carboxyl group) may also be used. Though an anionexchanger preferably carries a strongly basic anion-exchange group(quaternary ammonium group), an anion exchanger carrying a weakly basicanion-exchange group (tertiary or lower amino group) may also be used.The nonwoven fabric carrying a strongly basic anion-exchange group canbe prepared by, for example, the following method: A polyolefin nonwovenfabric having a fiber diameter of 20-50 μm and a porosity of about 90%is subjected to the so-called radiation graft polymerization, comprisingγ-ray irradiation onto the nonwoven fabric and the subsequent graftpolymerization, thereby introducing graft chains; and the graft chainsthus introduced are then aminated to introduce quaternary ammoniumgroups thereinto. The capacity of the ion-exchange groups introduced canbe determined by the amount of the graft chains introduced. The graftpolymerization may be conducted by the use of a monomer such as acrylicacid, styrene, glicidyl methacrylate, sodium styrenesulfonate orchloromethylstyrene. The amount of the graft chains can be controlled byadjusting the monomer concentration, the reaction temperature and thereaction time. Thus, the degree of grafting, i.e. the ratio of theweight of the nonwoven fabric after graft polymerization to the weightof the nonwoven fabric before graft polymerization, can be made 500% atits maximum. Consequently, the capacity of the ion-exchange groupsintroduced after graft polymerization can be made 5 meq/g at itsmaximum.

[0124] The nonwoven fabric carrying a strongly acidic cation-exchangegroup can be prepared by the following method: As in the case of thenonwoven fabric carrying a strongly basic anion-exchange group, apolyolefin nonwoven fabric having a fiber diameter of 20-50 μm and aporosity of about 90% is subjected to the so-called radiation graftpolymerization comprising γ-ray irradiation onto the nonwoven fabric andthe subsequent graft polymerization, thereby introducing graft chains;and the graft chains thus introduced are then treated with a heatedsulfuric acid to introduce sulfonic acid groups thereinto. If the graftchains are treated with a heated phosphoric acid, phosphate groups canbe introduced. The degree of grafting can reach 500% at its maximum, andthe capacity of the ion-exchange groups thus introduced after graftpolymerization can reach 5 meq/g at its maximum.

[0125] The base material of the ion exchanger 58 may be a polyolefinsuch as polyethylene or polypropylene, or any other organic polymer.Further, besides the form of a nonwoven fabric, the ion-exchanger may bein the form of a woven fabric, a sheet, a porous material, short fibersor net, etc.

[0126] When polyethylene or polypropylene is used as the base material,graft polymerization can be effected by first irradiating radioactiverays (γ-rays or electron beam) onto the base material (pre-irradiation)to thereby generate a radical, and then reacting the radical with amonomer, whereby uniform graft chains with few impurities can beobtained. When an organic polymer other than polyolefin is used as thebase material, on the other hand, radical polymerization can be effectedby impregnating the base material with a monomer and irradiatingradioactive rays (γ-rays, electron beam or UV-rays) onto the basematerial (simultaneous irradiation) Though this method fails to provideuniform graft chains, it is applicable to a wide variety of basematerials.

[0127] By using the ion exchanger 58 made of a nonwoven fabric, whichliquid can flows therethough, having an anion-exchange group or acation-exchange group, it becomes possible that pure water or ultrapurewater, or a liquid such as an electrolytic solution can freely movewithin the nonwoven fabric, and the ion-exchange reaction between ionsin the liquid and the ion-exchange group of the ion exchanger can beeasily taken place.

[0128] When the ion exchanger 58 has only one of anion-exchange groupand cation-exchange group, a limitation is imposed on electrolyticallyprocessible materials and, in addition, impurities are likely to formdue to the polarity. In order to solve this problem, the ion exchanger58 may have such a structure wherein anion exchangers having ananion-exchange group and cation exchangers having a cation-exchangegroup are concentrically disposed to constitute an integral structure.The anion exchangers and the cation exchangers may be superimposed onthe surface, to be processed, of a substrate. It may also be possible tomake the anion exchangers and the cation exchangers each in the shape ofa fan, and dispose them alternately. Alternatively, the ion exchanger 58may carry both of an anion-exchange group and a cation-exchange groupper se. Such an ion exchanger may include an amphoteric ion exchanger inwhich anion-exchange groups and cation-exchange groups are distributedrandomly, a bipolar ion exchanger in which anion-exchange groups andcation-exchange groups are present in layers, and a mosaic ion exchangerin which portions containing anion-exchange groups and portionscontaining cation-exchange groups are present in parallel in thethickness direction. Incidentally, it is of course possible toselectively use, as the ion exchange 58, one having an anion-exchangegroup or one having a cation-exchange group according to the material tobe processed.

[0129] The pivot arm 50, which moves up and down via a ball screw 68 bythe actuation of a motor 66 for vertical movement, for pivoting thesubstrate holder 52 is connected to the upper end of a pivot shaft 72that pivots by the actuation of a pivoting motor 70. The substrateholder 52 is connected to a motor 74 for rotation that is mounted on thefree end of the pivot arm 50, and is allowed to rotate by the actuationof the motor 74 for rotation.

[0130] The electrode section 60 is connected directly to a hollow motor76, and is allowed to make scroll movement (translational rotatingmovement) by the actuation of the hollow motor 76. A through-hole 60 aas a pure water supply section for supplying pure water, preferablyultrapure water, is formed in the central portion of the electrodesection 60. The through-hole 60 a is connected to a pure water supplypipe 80, that vertically extends inside the hollow motor 76, via athrough hole 78 a formed inside a crank shaft 78 connected directly to adrive shaft of the hollow motor 76 for making scroll movement. Purewater or ultrapure water is supplied through the through-hole 60 a, andvia the ion exchanger 58 having water absorption property, is suppliedto the entire processing surface of the substrate W.

[0131] Pure water herein refers to a water having an electricconductivity of not more than 10 μS/cm, and ultrapure water refers to awater having an electric conductivity of not more than 0.1 μS/cm.Instead of pure water, a liquid having an electric conductivity of notmore than 500 μS/cm or any electrolytic solution may be used. Bysupplying such a processing liquid during processing, the instabilityfactors of processing, such as process products and dissolved gases, canbe removed, and processing can be effected uniformly with goodreproducibility.

[0132] According to this embodiment, plurality of fan-shaped electrodeplates 82 are disposed in the surface of the electrode section 60 alongthe circumference direction, and the cathode and anode of a power source86 are alternately connected, via a control box 84, to the electrodeplates 82. The electrode plates 82 connected to the cathode of the powersource 86 become the processing electrodes 54 and the electrode plates82 connected to the anode of the power source 86 become the feedingelectrodes 56. This applies to processing of e.g. copper, becauseelectrolytic processing of copper proceeds on the cathode side.Depending upon a material to be processed, the cathode side can be afeeding electrode and the anode side can be a processing electrode. Morespecifically, when the material to be processed is copper, molybdenum,iron or the like, electrolytic processing proceeds on the cathode side,and therefore the electrode plates 82 connected to the cathode of thepower source 86 should be the processing electrodes 54 and the electrodeplates 82 connected to the anode should be the feeding electrodes 56. Inthe case of aluminum, silicon or the like, on the other hand,electrolytic processing proceeds on the anode side. Accordingly, theelectrode plates connected to the anode of the power source should bethe processing electrodes and the electrode plates connected to thecathode should be the feeding electrodes.

[0133] By thus disposing the processing electrodes 54 and the feedingelectrodes 56 separately and alternately in the circumferentialdirection of the electrode section 60, fixed feeding portions to supplyelectricity to a conductive film (portion to be processed) of thesubstrate is not needed, and processing can be effected to the entiresurface of the substrate. Further, be changing the positive and negativein a pulse manner, an electrolysis product can be dissolved and theflatness of the processed surface can be enhanced by the multiplexrepetition of processing.

[0134] With respect to the processing electrode 54 and the feedingelectrode 56, oxidation or dissolution thereof due to an electrolyticreaction is generally a problem. In view of this, it is preferred touse, as a base material of the feeding electrode 56, carbon, a noblemetal that is relatively inactive, a conductive oxide or a conductiveceramics, rather than a metal or metal compound widely used forelectrodes. A noble metal-based electrode may, for example, be oneobtained by plating or coating platinum or iridium onto a titaniumelectrode, and then sintering the coated electrode at a high temperatureto stabilize and strengthen the electrode. Ceramics products aregenerally obtained by heat-treating inorganic raw materials, andceramics products having various properties are produced from variousraw materials including oxides, carbides and nitrides of metals andnonmetals. Among them there are ceramics having an electricconductivity. When an electrode is oxidized, the value of the electricresistance generally increases to cause an increase of applied voltage.However, by protecting the surface of an electrode with a non-oxidativematerial such as platinum or with a conductive oxide such as an iridiumoxide, the increase of electric resistance due to oxidation of the basematerial of an electrode can be prevented.

[0135] When carrying out electrolytic processing of copper by using asthe ion exchanger 58 a cation exchanger having cation-exchange groups, aconsiderable proportion of the ion-exchange groups of the ion exchanger(cation exchanger) 58 is occupied by copper after the processing,leading to lowering of the processing efficiency of the next processing.When carrying out electrolytic processing of copper by using as the ionexchanger 58 an anion exchanger having anion-exchange groups, on theother hand, fine particles of a copper oxide are generated and theparticles adhere to the surface of the ion exchanger (anion exchanger)58. Such particles on the ion exchanger can contaminate the surface of anext substrate to be processed. The regeneration section 64 is providedfor regenerating such a consumed or contaminated ion exchanger 58,thereby removing the above drawbacks. The regeneration section 64 ismounted on the free end of a pivot arm 62 which is coupled to the upperend of a pivot shaft 90 that rotates by the actuation of a pivotingmotor 88. The regeneration section 64 includes a regeneration electrodeholder 94, a disc-shaped regeneration electrode 96 held with its surfacefacing downward by the regeneration electrode holder 94, and an ionexchanger 98 for regeneration, covering the entire surface (lowersurface) of the regeneration electrode 96. The regeneration electrode 96is designed to be large enough to entirely cover an electrode section 60even when the electrode section 60 makes a scroll movement. By thepivoting of the pivot arm 62, the regeneration electrode 96 moves to aposition at which it covers the entire surface of the electrode section60. At that position, the ion exchanger 98 can come close to or intocontact with the surface (upper surface) of the ion exchanger 58covering the electrode plates 82, consisting of the processingelectrodes 54 and the feeding electrodes 56, of the electrode section60.

[0136] The regeneration electrode 96 is to be electrically connected bya wire 100 to one of the electrodes (e.g. cathode) of a power source 86by means of a control box 84, while the electrode plates 82, consistingof the processing electrodes 54 and the feeding electrodes 56, are to beelectrically connected to the other electrode (e.g. anode) of the powersource 86. A regeneration power source 102 is thus constructed.

[0137] The ion exchanger 98 for regeneration has the same type ofion-exchange group as the ion exchanger 58 to be regenerated, mounted onthe electrode section 60. That is, when a cation exchanger having acation-exchange group is used as the ion exchanger 58, a cationexchanger is used also as the ion exchanger 98 for regeneration. When ananion exchanger having an anion-exchange group is used as the ionexchanger 58, an anion exchanger is used also as the ion exchanger 98for regeneration. When connecting, by means of the control box 84, theregeneration electrode 96 to one of the electrodes of the power source86 by the wire 100 and, at the same time, connecting the electrodeplates 82, consisting of the processing electrodes 54 and the feedingelectrodes 56, to the other electrode of the power source 86, asdescribed above, such control is made that the electrode on the ionexchanger 98 side, i.e. the regeneration electrode 96, should have theopposite polarity to the polarity of the ion exchangers 58, 98. Thus,when cation exchangers, having a cation-exchange group as anion-exchange group, are used as the ion exchangers 58, 98, such controlis made that the regeneration electrode 96 should become a cathode andthe electrode plates 82 should become an anode. Conversely, when anionexchangers are used as the ion exchangers 58, 98, the regenerationelectrode 96 should become an anode and the electrode plates 82 shouldbecome a cathode.

[0138] Next, a substrate processing (electrolytic processing) and aregeneration treatment by the substrate processing apparatus will bedescribed.

[0139] First, a substrate W, as shown in FIGS. 10 and 11, is attractedand held by the substrate holder 52 of the electrolytic processingapparatus 48 a, and the substrate holder 52 is moved by the pivot arm 50to a processing position right above the electrode section 60. Thesubstrate holder 52 is then lowered by the actuation of the motor 66 forvertical movement, so that the substrate W held by the substrate holder52 contacts or gets close to the surface of the ion exchanger 58 mountedon the upper surface of the electrode section 60.

[0140] Next, via a control box 84, a given voltage is applied from thepower source 86 between the processing electrodes 54 and the feedingelectrodes 56, while the substrate holder 52 is rotated and theelectrode section 60 is made scroll movement. Specifically, the ionexchanger 58 and the electrode section 60 are contacted or got close toeach other, and are moved relatively. The electrode section 60 may berotated instead of making scroll movement. Furthermore, one of the ionexchanger 58 and the electrode section 60 may be moved. At the sametime, pure water or ultrapure water is supplied, through thethrough-hole 60 a, from beneath the electrode section 60 to the uppersurface thereof, thereby filling pure water or ultrapure water into thespace between the processing electrode 54, feeding electrode 56 and thesubstrate W. Thereby, electrolytic processing of the copper film 6, asshown in FIG. 1B, for example, formed on the substrate W is effected bythe electrolytic reaction and the movement of ions produced in the ionexchanger. More specifically, by allowing pure water or ultrapure waterto flow within the ion exchanger 58, the electrolytic processingefficiency can be enhanced.

[0141] After completion of the electrolytic processing, via the controlbox 84, the power source 84 is disconnected from the processingelectrode 54 and feeding electrode 56, the rotation of the substrateholder 52 and the scroll movement of the electrode section 60 arestopped. Thereafter, the substrate holder 52 is raised, the pivot arm 50is pivoted, and processed substrate W is transferred to next process.

[0142] This embodiment shows the case of supplying pure water,preferably ultrapure water, to the space between the electrode section60 and the substrate W. The use of pure water or ultrapure watercontaining no electrolyte upon electrolytic processing can prevent extraimpurities such as an electrolyte from adhering to and remaining on thesurface of the substrate W. Further, copper ions or the like dissolvedduring electrolytic processing are immediately caught by the ionexchanger 58 through the ion-exchange reaction. This can prevent thedissolved copper ions or the like from re-precipitating on the otherportions of the substrate W, or from being oxidized to become fineparticles which contaminate the surface of the substrate W.

[0143] Ultrapure water has a high resistivity, and therefore an electriccurrent is hard to flow therethrough. A lowering of the electricresistance is made by shortening a distance between the electrode andworkpiece or interposing the ion exchanger between the electrode andworkpiece. Further, an electrolytic solution, when used in combinationwith electrolytic solutions, can further lower the electric resistanceand reduce the power consumption. When electrolytic processing isconducted by using an electrolytic solution, the portion of a workpiecethat undergoes processing ranges over a slightly wider area than thearea of the processing electrode. In the case of the combined use ofultrapure water and the ion exchanger, on the other hand, since almostno electric current flows through ultrapure water, electric processingis effected only within the area of a workpiece that is equal to thearea of the processing electrode and the ion exchanger.

[0144] It is possible to use, instead of pure water or ultrapure water,an electrolytic solution obtained by adding an electrolyte to pure wateror ultrapure water. The use of such an electrolytic solution can furtherlower the electric resistance and reduce the power consumption. Asolution of a neutral salt such as NaCl or Na₂SO₄, a solution of an acidsuch as HCl or H₂SO₄, or a solution of an alkali such as ammonia, may beused as the electrolytic solution, and these solutions may beselectively used according to the properties of the workpiece. When theelectrolytic solution is used, it is preferred to provide a slightinterspace between the substrate W and the ion exchanger 58 so that theyare not in contact with each other. Further, it is also possible to use,instead of pure water or ultrapure water, a liquid obtained by adding asurfactant or the like to pure water or ultrapure water, and having anelectric conductivity of not more than 500 μS/cm, preferably not morethan 50 μS/cm, more preferably not more than 0.1 μS/cm (resistivity ofnot less than 10 MΩ·cm). Due to the presence of a surfactant in purewater or ultrapure water, the liquid can form a layer, which functionsto inhibit ion migration evenly, at the interface between the substrateW and the ion exchanger 58, thereby moderating concentration of ionexchange (metal dissolution) to enhance the flatness of the processedsurface. The surfactant concentration is desirably not more than 100ppm. When the value of the electric conductivity is too high, thecurrent efficiency is lowered and the processing rate is decreased. Theuse of the liquid having an electric conductivity of not more than 500μS/cm, preferably not more than 50 μS/cm, more preferably not more than0.1 μS/cm, can attain a desired processing rate.

[0145] If a voltage is raised to increase the current density in orderto enhance the processing rate, an electric discharge can occur when theelectric resistance between the electrode and the substrate (workpieceto be processed) is large. The occurrence of electric discharge causespitching on the surface of the workpiece, thus failing to form an evenand flat processed surface. To the contrary, since the electricresistance is very small when the ion exchanger 58 is in contact withthe substrate W, the occurrence of an electric discharge can be avoided.

[0146] Next, at a desired time, for example, after an elapse of apredetermined time or after having processed a predetermined member ofsubstrates, the ion exchanger 58, which has been used in theelectrolytic processing, is subjected to a regeneration treatment. Theregeneration treatment will now be described with reference to FIGS. 12and 13.

[0147] First, the substrate holder 52 is retreated from above theelectrode section 60, and then the pivot arm 62 is pivoted to move theregeneration section 64 to above the electrode section 60, so that thelower surface of the ion exchanger 98 for regeneration of theregeneration section 64 is brought close to or into contact with theupper surface of the ion exchanger 58 to be regenerated, mounted on theupper surface of the electrode section 60.

[0148] By means of the control box 84, one of the electrodes (e.g.cathode) of the power source 86 is connected to the regenerationelectrode 96 and the other electrode (e.g. anode) is connected to theelectrode plates 82 consisting of the processing electrodes 54 and thefeeding electrodes 56, thereby applying a voltage between theregeneration electrode 96 and the electrode plates 82, while theelectrode section 60 is allowed to make a scroll movement. At the sametime, pure water or ultrapure water is supplied from below the electrodesection 60 through the through-hole 60 a to the upper surface of theelectrode section 60 so as to fill the area between the regenerationelectrode 96 and the electrode plates 82 with pure water or ultrapurewater, thereby immersing the ion exchanger 58 to be regenerated and theion exchanger 98 for regeneration in pure water or ultrapure water.

[0149] Upon the electrical connection, as described above, such controlis made by means of the control box 84 that the electrode on the ionexchanger 98 side, i.e. the regeneration electrode 96, should have theopposite polarity to the polarity of the ion exchangers 58, 98. Thus,when cation exchangers are used as the ion exchangers 58, 98, theregeneration electrode 96 should become a cathode and the electrodeplates 82 should become an anode. Conversely, when anion exchangers areused as the ion exchangers 58, 98, the regeneration electrode 96 shouldbecome an anode and the electrode plates 82 should become a cathode.

[0150] By the above operation, through an ion-exchange reactionutilizing the ion exchangers 58, 98 as a solid electrolyte, ions in theion exchanger 58 to be regenerated are moved into the ion exchanger 98for regeneration. Regeneration of the ion exchanger 58 is thus effected.When cation exchangers are used as the ion exchangers 58, 98, cationstaken in the ion exchanger 58 to be regenerated move into the ionexchanger 98 for regeneration; when anion exchangers are used as the ionexchangers 58, 98, anions taken in the ion exchanger 58 to beregenerated move into the ion exchanger 98 for regeneration, whereby theion exchanger 58 is regenerated.

[0151] As described above, instead of pure water or ultrapure water, itis also possible to use a liquid having an electric conductivity of notmore than 500 μS/cm or an electrolytic solution.

[0152] After completion of the regeneration, electrical connectionsbetween the power source 86 and the electrodes plates 82 and between thepower source 86 and the regeneration electrode 96 are shut off by meansof the control box 84, and the scroll movement of the electrode section60 is stopped. Thereafter, the pivot arm 62 is pivoted to return theregeneration section 64 to the original position.

[0153]FIG. 14 shows a substrate processing apparatus provided with theelectrolytic processing apparatus 48 a described above. As shown in FIG.14, the substrate processing apparatus comprises a pair ofloading/unloading units 110 as a carry-in and carry-out section forcarrying in and carrying out a cassette housing a substrate W, e.g. asubstrate W as shown in FIG. 1B, which has in its surface a copper film6 as a conductor film (portion to be processed), a reversing machine 112for reversing the substrate W, and an electrolytic processing apparatus48 a, which are disposed in series. A transfer robot 114 as a transferdevice is provided which can move parallel to these apparatuses fortransporting and transferring the substrate W therebetween. Thesubstrate processing apparatus is also provided with a monitor 116, formonitoring a voltage applied between processing electrodes 54 andfeeding electrodes 56 upon electrolytic processing in the electrolyticprocessing apparatus 48 a, or an electric current flowing therebetween.The monitor can monitor at least one of an electrolysis current andelectrolysis time, and/or the quantity of electricity, when the voltageis applied between the electrodes plates 82, consisting of theprocessing electrodes 54 and feeding electrodes 56, and the regenerationelectrode 96 upon regeneration treatment.

[0154] Next, substrate processing (electrolytic processing) by thesubstrate processing apparatus will be described. First, a substrate W,e.g. a substrate which has in its surface a copper film 6 (see FIG. 1B)as a conductor film (portion to be processed) is taken by the transferrobot 114 out of the cassette housing substrates and set in theloading/unloading unit 110. If necessary, the substrate W is transferredto the reversing machine 112 to reverse the substrate W. The substrate Wis then attracted and held by the substrate holder 52 of theelectrolytic processing apparatus 48 a. Then, the electrolyticprocessing of the substrate W can be conducted as the same mannerdescribed above.

[0155] At this time, the monitor 116 monitors the voltage appliedbetween the processing electrodes 54 and the feeding electrodes 56 orthe electric current flowing therebetween to detect the end point(terminal of processing). It is noted in this connection that inelectrolytic processing an electric current (applied voltage) varies,depending upon the material to be processed, even with the same voltage(electric current). Therefore, the end point can surely be detected bythe monitoring of changes in electric current or in voltage.

[0156] After completion of the electrolytic processing, the substrateholder 52 is raised, and substrate W is carried to the transfer robot114 by pivoting the pivot arm 50. The transfer robot 114 takes thesubstrate W from the substrate holder 52 and, if necessary, transfersthe substrate W to the reversing machine 112 for reversing it, and thenreturns the substrate W to the cassette in the loading/unloading unit110.

[0157] When carrying out regeneration of the ion exchanger 58 in theabove-described manner, at least one of the electrolysis current andtime, and/or the quantity of electricity, as observed when a voltage isapplied between the electrode plates 82, consisting of the processingelectrodes 54 and the feeding electrodes 56, and the regenerationelectrode 96, is monitored by the monitor 116. The regeneration amountof an ion exchanger is governed by the product of the electrolysiscurrent and the electrolysis time, i.e. the quantity of electricity.Accordingly, by monitoring at least one of the electrolysis current andtime, and/or the quantity of electricity by the monitor 116, it becomespossible to control the regeneration amount and detect the end point ofregeneration.

[0158]FIGS. 15 and 16 show an electrolytic processing apparatus 48 bhaving a regeneration device of an ion exchanger according to anotherembodiment of the present invention. In this electrolytic processingapparatus 48 b, the positional relationship between the substrate holder52 and the electrode section 60 in the preceding embodiments isreversed, and the substrate W is held with its surface facing upward(so-called “face-up” manner) so that electrolytic processing isconducted to the upper surface of the substrate. Thus, the substrateholder 52 is disposed beneath the electrode section 60, holds thesubstrate W with its surface facing upward, and rotates about its ownaxis by the actuation of the motor 74 for rotation. On the other hand,the electrode section 60, which has the processing electrodes 54 and thefeeding electrodes 56 that are covered with the ion exchanger 58, isdisposed above the substrate holder 52, is held with its front surfacedownward by the pivot arm 50 at the free end thereof, and rotates aboutits own axis by the actuation of the hollow motor 76. Further, wiresextending from the power source 86 pass through a hollow portion formedin the pivot shaft 72 and reach the slip ring 120, and further passthrough the hollow portion of the hollow motor 76 and reach theprocessing electrodes 54 and the feeding electrodes 56 to apply avoltage therebetween. According to this embodiment, the ion exchanger 58is designed to have a diameter which is larger than that of thesubstrate W, but the ion exchanger which has a diameter smaller than thesubstrate W may be used.

[0159] Pure water or ultrapure water is supplied from the pure watersupply pipe 80, via the through-hole 60 a formed in the central portionof the electrode section 60, to the front surface (upper surface) of thesubstrate W from upper side of the substrate W.

[0160] As shown by solid lines in FIG. 15, in operation, the electrodesection 60 is lowered so that the substrate W held by the substrateholder 52 contacts or gets close to the surface of the ion exchanger 58mounted on the upper surface of the electrode section 60. Next, a givenvoltage is applied between the processing electrodes 54 and the feedingelectrodes 56, while applying pure water or ultrapure water to the uppersurface of the substrate W. At the same time, the substrate holder 52and the electrode section 60 are rotated, and the electrode section 60is pivoted. Thereby, electrolytic processing of the surface of thesubstrate is effected.

[0161] Further, the regeneration section 64 for regenerating the ionexchanger 58 mounted on the electrode section 60 is provided by the sideof the substrate holder 52. The regeneration section 64 includes theregeneration electrode holder 94 joined to the upper end of a supportpost 122, the regeneration electrode 96 held by the regenerationelectrode holder 94, and the ion exchanger 98 for regeneration, coveringthe surface (upper surface) of the regeneration electrode 96. As shownby the imaginary lines in FIG. 15, the electrode section 60 is moved toright above the regeneration section 64 by pivoting the pivot arm 50,and is then lowered so as to bring the ion exchanger 58 to beregenerated, mounted on the electrode section 60, close to or intocontact with the ion exchanger 98 for regeneration of the regenerationsection 64. While rotating and, of necessary, pivoting the electrodesection 60, a given voltage is applied from the regeneration powersource 102 to between the electrode plates 82, consisting of theprocessing electrodes 54 and the feeding electrodes 56, and theregeneration electrode 96, thereby regenerating the ion exchanger 58.The ion exchanger 58 after the regeneration is rinsed e.g. withultrapure water.

[0162]FIG. 17 shows an electrolytic processing apparatus 48 c having aregeneration device of an ion exchanger according to still anotherembodiment of the present invention. The electrolytic processingapparatus 48 c differs from the electrolytic processing apparatus 48 bshown in FIGS. 15 and 16 in that the ion exchanger 58 is of athree-layer structure (lamination) consisting of a pair of stronglyacidic cation-exchange fibers 130, 132 and a strongly acidiccation-exchange membrane 134 interposed between the fibers 130,132, forexample. The other construction is the same as shown in FIGS. 15 and 16.The ion exchanger 58 may consist of any ion exchanger materials.Furthermore, the number of the laminated layers is not limited to three.

[0163] By making the ion exchanger 58 a multi-layer structure consistingof laminated layers of ion-exchange materials, such as a nonwovenfabric, a woven fabric and a porous membrane, it is possible to increasethe total ion exchange capacity of the ion exchanger 58, wherebyformation of an oxide, for example in removal (polishing) processing ofcopper, can be restrained to thereby avoid the oxide adversely affectingthe processing rate. Without using a multi-layer structure, an ionexchange capacity may be increased by using a thick ion exchanger ofsingle layer. In this regard, when the total ion exchange capacity of anion exchanger is smaller than the amount of copper ions taken in the ionexchanger during removal processing, the oxide should inevitably beformed on the surface or in the inside of the ion exchanger, whichadversely affects the processing rate. Thus, the formation of the oxideis governed by the ion exchange capacity of an ion exchanger, and copperions exceeding the capacity should become the oxide. The formation of anoxide can thus be effectively restrained by using, as the ion exchanger,a multi-layer ion exchanger composed of laminated layers of ion-exchangematerials which has enhanced total ion exchange capacity. The formationof an oxide can be restrained by regenerating the ion exchanger tosuppress the accumulation of the copper ions or the like inside the ionexchanger.

[0164] According to this embodiment, as with the embodiment shown inFIGS. 14 and 15, the ion exchanger 58 of a multi-layer structure isregenerated in the regeneration section 64 at a desired time. By theregeneration, the plurality of ion-exchange materials constituting theion exchanger 58, such as the strongly acidic cation-exchange fibers130, 132 and the strongly acidic cation-exchange membrane 134 or thelike, can be regenerated simultaneously.

[0165] This embodiment employs a laminate of a plurality of ion-exchangematerials as the ion exchanger to be regenerated. It is also possible touse a laminate of a plurality of ion-exchange materials as the ionexchanger for regeneration. When the ion exchanger for regeneration isconfigured by a lamination of plurality of ion-exchange materials, thesubstantial ion-exchanger capacity of the ion exchanger for regenerationis increased, and more ion exchanger (ion exchanger to be regenerated)can be regenerated continuously.

[0166] According to the above-described embodiments, the liquid supplysection for supplying a liquid between the substrate and the ionexchanger upon the electrolytic processing is utilized also as theliquid supply section for supplying a liquid between the pair ofelectrodes to immerse the ion exchanger to be regenerated and the ionexchanger for regeneration in the liquid. It is, however, possible toprovide two independent liquid supply sections.

[0167] Further according to the above embodiments, the regenerationsection is provided with the ion exchanger for regeneration so that ionsin the ion exchanger to be regenerated can move into the ion exchangerfor regeneration during the regeneration treatment. This can prevent theions, moving from the ion exchanger to be regenerated, from attaching tothe electrode, thus preventing a solid matter adhering to the electrodefrom contaminating the regenerated ion exchanger. The ion exchanger forregeneration may however be omitted.

[0168]FIGS. 18 and 19 show an electrolytic processing apparatus 48 dhaving an ion exchanger regeneration device according to still anotherembodiment of the present invention. The electrolytic processingapparatus 48 d differs from the above-described embodiment shown inFIGS. 10 through 13 in the use of the below-described regenerationsection as the regeneration section 64, mounted to the free end of thepivot arm 62 which is coupled to the upper end of the pivot shaft 96that rotates by the actuation of the pivoting motor 94, for regeneratingthe ion exchanger 58. The other construction is the same as theembodiment shown in FIGS. 10 through 13.

[0169] The regeneration section 64 includes a disc-shaped regenerationelectrode holder 198. The regeneration electrode holder 198 has adownwardly-open circular depression 198 a. The opening of the depression198 a is closed with a partition 202, whereby a discharge portion 200,defined by the depression 198 a and the partition 202, is formed. Adisc-shaped regeneration electrode 204 is mounted in the bottom of thedepression 198 a. Further, a liquid inlet 198 b and a liquid outlet 198c, communicating with peripheral portions of the discharge portion 200,are respectively provided at the both end portions in the diametricaldirection of the regeneration electrode holder 198. The liquid inlet 198b and the liquid outlet 198 c are respectively connected to a liquidinlet pipe 206 and to a liquid outlet pipe 206 b. A liquid is suppliedfrom the liquid inlet pipe 206 into the discharge portion 200. Theliquid supplied fills the discharge portion 200, so that theregeneration electrode 204 is immersed in the liquid. Thereafter, theliquid supplied into the discharge portion 200 flows in one in directionin the discharge portion 200 and is discharged sequentially from theliquid outlet pipe 206 b.

[0170] As described below, it is desired that the partition 202 nothinder the migration therethrough of impurity ions removed from the ionexchanger 58 to be regenerated and inhibit permeation therethrough ofthe liquid (including ions in the liquid) flowing between the partition202 and the regeneration electrode 204 into the ion exchanger 58 side.In this regard, ion exchangers permit selective permeation therethroughof cations or anions. A suitable ion exchanger as a partition can beselected. Further, a film-type ion exchanger as a partition can preventintrusion of the liquid flowing between the partition 202 and theregeneration electrode 204 into the to-be-regenerated ion exchanger 58side. Thus, a suitably selected film-type ion exchanger can meet theabove requirements for the partition 202.

[0171] It is desired that the liquid to be supplied into the dischargeportion 200 be a liquid, such as an electrolytic solution, which has ahigh electric conductivity and does not form a hardly soluble orinsoluble compound through a reaction with ions removed from the ionexchanger to be processed. Thus, as described below, the liquid is fordischarging those ions, which have moved from the ion exchanger 58 to beregenerated and passed through the partition 202, out of the system bythe flow of the liquid. The above liquid having a high conductivity,because of its low electric resistance, can reduce the power consumptionin the regeneration section. Further the above liquid, which does notform an insoluble compound (by-product) through a reaction with theimpurity ions, can prevent adhesion of a solid matter to the partition202. A suitable liquid may be chosen depending upon the kind of theimpurity ion to be discharged. For example, when regenerating an ionexchanger that was used in electrolytic polishing of copper, sulfuricacid with a concentration of 1 wt % or higher may be used.

[0172] The regeneration electrode 204 is to be electrically connected bythe wire 100 to one of the electrodes (e.g. cathode) of the power source86 by means of control box 84, while the electrode plates 82, consistingof the processing electrodes 54 and the feeding electrodes 56, are to beelectrically connected to the other electrode (e.g. anode) of the powersource 86. A regeneration power source 102 is thus constructed.

[0173] According to this embodiment, the ion exchanger used as thepartition 202 has the same type of ion-exchange group as the ionexchanger 58 to be regenerated mounted in the electrode section 60. Thatis, when a cation exchanger having a cation-exchange group is used asthe ion exchanger 58, a cation exchanger is used also as the partition(ion exchanger) 202. When an anion exchanger having an anion-exchangegroup is used as the ion exchanger 58, an anion exchanger is used alsoas the partition (ion exchanger) 202.

[0174] Further, when connecting, by means of the control box 84, theregeneration electrode 204 to one of the electrodes of the power source86 by the wire 100 and, at the same time, connecting the electrodeplates 82, consisting of the processing electrodes 54 and the feedingelectrodes 56, to the other electrode of the power source 86, asdescribed above, such control is made that when a cation exchanger isused as the ion exchanger 58 to be regenerated, the regenerationelectrode 204 should become a cathode, and when an anion exchanger isused as the exchanger 58, the regeneration electrode 204 should becomean anode.

[0175] Regeneration treatment as performed by the electrolyticprocessing apparatus will now be described with reference to FIG. 19.

[0176] First, the substrate holder 52 is retreated from above theelectrode section 60, and then the pivot arm 62 is pivoted to move theregeneration section 64 to above the electrode section 60. Theregeneration section 64 is then lowered so that the lower surface of thepartition 202 of the regeneration section 64 is brought close to or intocontact with the upper surface of the ion exchanger 58 to beregenerated, mounted in the upper surface of the electrode section 60.

[0177] By means of the control box 84, one of the electrodes (e.g.cathode) of the power source 86 is connected to the regenerationelectrode 204 and the other electrode (e.g. anode) is connected to theelectrode plates 82 consisting of the processing electrodes 54 and thefeeding electrodes 56, thereby applying a voltage between theregeneration electrode 204 and the electrode plates 82, while theelectrode section 60 is allowed to make a scroll movement. The feedingelectrodes may not be in electrical connection upon regeneration. At thesame time, pure water or ultrapure water is supplied from below theelectrode section 60 through the through-hole 60 a to the upper surfaceof the electrode section 60 so as to fill the area between the partition202 and the electrode plates 82 with pure water or ultrapure water,thereby immersing the ion exchanger 58 to be regenerated in pure wateror ultrapure water, while a liquid is supplied into the dischargeportion 200 provided inside the regeneration electrode holder 98 so asto fill the discharge portion 200 with the liquid, thereby immersing theregeneration electrode 204 in the liquid and allowing the liquid to flowin one direction in the discharge portion 200 and to be discharged fromthe liquid outlet 198 c.

[0178] Upon the electrical connection, as described above, such controlis made by means of the control box 84 that the regeneration electrode204 should have the opposite polarity to the polarity of the ionexchanger 58 (and of the partition 202). Thus, when a cation exchangeris used as the ion exchanger 58 (and as the partition 202), theregeneration electrode 204 should become a cathode and the electrodeplates 82 should become an anode. Conversely, when an anion exchanger isused as the ion exchanger 58 (and as the partition 202), theregeneration electrode 204 should become an anode and the electrodeplates 82 a cathode.

[0179] By the above operation, ions in the ion exchanger 58 to beregenerated are moved toward the regeneration electrode 204, passedthrough the partition 202, and introduced into the discharge portion200. The ions thus moved into the discharge portion 200 are dischargedout of the system by the flow of the liquid supplied into the dischargeportion 200. Regeneration of the ion exchanger 58 is thus effected. Whena cation exchanger is used as the ion exchanger 58, cations taken in theion exchanger 58 to be regenerated pass through the partition 202 andmove into the discharge portion 200; when an anion exchanger is used,anions taken in the ion exchanger 58 to be regenerated pass through thepartition 202 and move into the discharge portion 200, whereby the ionexchanger 58 is regenerated.

[0180] In the above regeneration treatment, as descried above, an ionexchanger having the same type of ion-exchange group as the ionexchanger 58 to be regenerated is used as the partition 202. Thisprevents migration of impurity ions in the ion exchanger 58 through thepartition (ion exchanger) 202 from being hindered by the partition 202,thereby preventing an increase in the power consumption. Further, thisinhibits permeation through the partition 202 of the liquid (includingions in the liquid) flowing between the partition 202 and theregeneration electrode 204, thus inhibiting movement of the liquid tothe ion exchanger 58 side and preventing re-contamination of theregenerated ion exchanger 58. Furthermore, preferably used as the liquidto be supplied between the partition 202 and the regeneration electrode204 is a liquid having an electric conductivity of not less than 50μS/cm which does not form a hardly soluble or insoluble compound througha reaction with ions removed from the ion exchanger 58. Such a liquid,because of its low electric resistance, can reduce the power consumptionin the regeneration section. Moreover the liquid does not form aninsoluble compound (by-product) through a reaction with an impurity ion.In this regard, an insoluble compound, if formed, will adhere to thepartition 202 whereby the electric resistance between the regenerationelectrode 204 and the electrode plates 82 will be changed, making itdifficult to control the electrolysis current. Such a problem can thusbe prevented. As with the above-described embodiments, instead of usingpure water or ultrapure water, it is possible to use a liquid having anelectric conductivity of not more than 500 μS/cm or an electrolyticsolution.

[0181] After completion of the regeneration, electrical connectionsbetween the power source 86 and the electrodes 82 and between the powersource 86 and the regeneration electrode 204 are shut off by means ofthe control box 84, and, after raising the regeneration section 64, thescroll movement of the electrode section 60 is stopped. Thereafter, thepivot arm 62 is pivoted to return the regeneration section 64 to theoriginal position. According to the present invention, as describedhereinabove, regeneration of an ion exchanger can be carried out easilyand quickly through an electrochemical reaction. By carrying out such anion exchanger regeneration e.g. in an electrolytic processing apparatus,the stoppage time of electrolytic processing can be shortened and theprocessing efficiency of the apparatus can be enhanced. Further, thepresent invention can minimize contamination of the regenerated ionexchanger with a chemical liquid and can also minimize a load uponcleaning of the regenerated ion exchanger.

[0182]FIGS. 21 and 22 show an electrolytic processing apparatus 450according to another embodiment of the present invention. Thiselectrolytic processing apparatus 450 includes a substrate holder 454,supported at the free end of a pivot arm 452 that can pivothorizontally, for attracting and holding the substrate W with its frontsurface facing downward (so-called “face-down” manner), a disc-shapedelectrode section 462, made of an insulating material, has fan-shapedprocessing electrodes 456 and feeding electrodes 458 embedded therein,that are disposed alternately with their surfaces (upper faces) exposed,and a film-like ion exchanger 460 mounted on the electrode section 462so as to cover the surfaces of the processing electrodes 456 and thefeeding electrodes 458.

[0183] This embodiment uses, merely as an example of the electrodesection 462 having the processing electrodes 456 and the feedingelectrodes 458, such one that has a diameter a little longer than thatof the substrate W held by the substrate holder 454 so that the entiresurface of the substrate W may undergo electrolytic processing by makinga scroll movement of the electrode section 462.

[0184] The pivot arm 452, which moves up and down via a ball screw 466by the actuation of a motor 464 for vertical movement, for pivoting thesubstrate holder 454 is connected to the upper end of a pivot shaft 470that pivots by the actuation of a pivoting motor 468. The substrateholder 454 is connected to a motor 475 for rotation that is mounted onthe free end of the pivot arm 452, and is allowed to rotate by theactuation of the motor 472 for rotation.

[0185] The electrode section 462 is connected directly to a hollow motor474, and is allowed to make scroll movement (translational rotatingmovement) by the actuation of the hollow motor 474. A through-hole 462 ais formed in the central portion of the electrode section 462. Thethrough-hole 462 a is connected to a electrolytic processing liquidsupply section 478 for supplying a processing liquid for electrolyticprocessing such as pure water, preferably ultrapure water, and connectsto an electrolytic processing liquid supply pipe 478 that extends insidethe hollow motor 474. The processing liquid such as pure water orultrapure water is supplied through the through-hole 462 a to the uppersurface of the electrode section 462, and spreads to the entireprocessing surface of the substrate W through the ion exchanger 460having water absorbing property.

[0186] According to this embodiment, fan-shaped electrode plates 480 aredisposed in the electrode section 462 along the circumference direction,and the cathode and anode of a processing power source 484 arealternately connected, via a control box 484, to the electrode plates480. The electrode plates 480 connected to the cathode of the processingpower source 484 become the processing electrodes 456 and the electrodeplates 480 connected to the anode of the processing power source 484become the feeding electrodes 458.

[0187] Further according to this embodiment, a cation exchanger is usedas the ion exchanger 460, and is partly regenerated the ion exchanger(cation exchanger) 460 which covers the processing electrodes 456.

[0188] Each processing electrode 456 is embedded in a depression 462 bprovided in the electrode section 462, and each feeding electrode 458 isembedded in a depression 462 c provided in the electrode section 462.The depression 462 b for embedding the processing electrode 456 therein,which is designed to be deeper than the depression 462 c for embeddingthe feeding electrode 458 therein, provides a regeneration section 490.

[0189] The regeneration section 490 includes a partition 492 that closesthe opening of the depression 462 b. By thus closing the opening of thedepression 462 b with the partition 492, a discharge portion 494 isformed between the processing electrode 456 and the partition 492.Further, the electrode section 462 is provided with a discharging liquidsupply inlet 462 d which is connected to a discharging liquid supplypipe 498 that is connected to a discharging liquid supply section 496for supplying a discharging liquid for discharging contaminants andextends in the hollow portion of the hollow motor 474, and which extendshorizontally and opens to the discharge portion 492; and a dischargingliquid discharge outlet 462 e which extends horizontally from the outerperiphery of the discharge portion 494 and opens at the outercircumferential surface of the electrode section 462. A dischargingliquid is supplied through the discharging liquid supply inlet 462 dinto the discharge portion 494. The discharging liquid thus suppliedinto the discharge portion 494 fills the discharge portion 494, so thatthe processing electrode 456 is immersed in the discharging liquid.Thereafter, the discharging liquid supplied into the discharge portion494 flows in one direction in the discharge portion 494 and isdischarged sequentially from the discharging liquid discharge outlet 462e.

[0190] As described below, it is desired that the partition 492 does nothinder the migration therethrough of impurity ions removed from the ionexchanger 460 to be regenerated and inhibit permeation therethrough ofthe discharging liquid (including ions in the liquid) flowing betweenthe partition 492 and the processing electrode 456 into the ionexchanger 460 side. In this regard, ion exchangers permit selectivepermeation therethrough of cations or anions. A suitable ion exchangeras a partition can be selected. Further, a film-type ion exchanger as apartition can prevent intrusion of the discharging liquid flowingbetween the partition 492 and the processing electrode 456 into the ionexchanger 460 side. Thus, a suitably selected film-type ion exchangercan meet the above requirements for the partition 492.

[0191] As described above, it is desired that the discharging liquid tobe supplied into the discharging portion 494 be a liquid which has ahigh electric conductivity, e.g. not less than 50 μS/cm, and which doesnot form a hardly soluble or insoluble compound through a reaction withions removed from the ion exchanger 460.

[0192] According to this embodiment, an ion exchanger having the sametype of ion-exchange group as the ion exchanger 460 to be regenerated isused as the partition 492. That is, a cation exchanger is used as thepartition 492. Such a partition (ion exchanger) 492 can permitpermeation therethrough of only those ions as coming from the ionexchanger (cation exchanger) 460 and inhibit migration therethrough ofions in the discharging liquid flowing in the discharging portion 494into the ion exchanger 460 side.

[0193] When an anion exchanger having an anion-exchange group is used asthe ion exchanger to be regenerated, it is preferred to use an anionexchanger as the partition (ion exchanger). Next, a substrate processing(electrolytic processing) and a regeneration treatment by theelectrolytic processing apparatus 450 will be described.

[0194] First, a substrate W is attracted and held by the substrateholder 454 of the electrolytic processing apparatus 450, and thesubstrate holder 454 is moved by the pivot arm 452 to a processingposition right above the electrode section 462. The substrate holder 454is then lowered by the actuation of the motor 464 for vertical movement,so that the substrate W held by the substrate holder 454 contacts orgets close to the surface of the ion exchanger 460 mounted on the uppersurface of the electrode section 460.

[0195] Next, via a control box 482, a given voltage is applied from theprocessing power source 484 between the processing electrodes 456 andthe feeding electrodes 458, while the substrate holder 454 is rotatedand the electrode section 462 is made scroll movement. Specifically, theion exchanger 460 and the electrode section 454 are contacted or gotclose to each other, and are moved relatively. The electrode section 462may be rotated instead of making scroll movement. Furthermore, one ofthe substrate holder 454 and the electrode section 462 may be moved. Atthe same time, a processing liquid such as pure water or ultrapure wateris supplied, through the through-hole 462 a, from beneath the electrodesection 462 to the upper surface thereof, thereby filling the processingliquid into the space between the processing electrode 456, the feedingelectrode 458 and the substrate W. Thereby, electrolytic processing ofthe copper film 6, as shown in FIG. 1B, for example, formed on thesubstrate W is effected by the electrolytic reaction and the movement ofions produced in the ion exchanger. More specifically, by allowing purewater or ultrapure water to flow within the ion exchanger 460, theelectrolytic processing efficiency can be enhanced.

[0196] At the same time, a discharging liquid is supplied through thedischarging liquid supply inlet 462 d into the discharge portion 494provided in the regeneration section 490, thereby filling the dischargeportion 494 with the discharging liquid and immersing the processingelectrode 456 in the discharging liquid, and allowing the dischargingliquid to flow outwardly in the discharge portion 494 and be dischargedfrom the discharging liquid discharge outlet 462 e.

[0197] By the above operation, through an ion-exchange reactionutilizing the ion exchanger 460 as a solid electrolyte, ions in the ionexchanger 460 to be regenerated are moved toward the processingelectrode 456, passed through the partition 492, and introduced into thedischarge portion 494. The ions thus moved into the discharge portion494 are discharged out of the system by the flow of the dischargingliquid supplied into the discharge portion 494. Regeneration of the ionexchanger 460 is thus effected. When a cation exchanger is used as theion exchanger 460, cations taken in the ion exchanger 460 to beregenerated pass through the partition 492 and move into the dischargeportion 494; when an anion exchanger is used, anions taken in the ionexchanger 460 to be regenerated pass through the partition 492 and moveinto the discharge portion 494, whereby the ion exchanger 460 isregenerated.

[0198] In the above regeneration treatment, as descried above, an ionexchanger having the same type of ion-exchange group as the ionexchanger 460 to be regenerated is used as the partition 492. Thisprevents migration of impurity ions in the ion exchanger 460 through thepartition (ion exchanger) 492 from being hindered by the partition 492,thereby preventing an increase in the power consumption. Further, thisinhibits permeation through the partition 492 of the discharging liquid(including ions in the liquid) flowing between the partition 492 and theprocessing electrode 456, thus inhibiting movement of the dischargingliquid to the ion exchanger 460 side and preventing re-contamination ofthe regenerated ion exchanger 460. Furthermore, preferably used as thedischarging liquid to be supplied between the partition 492 and theregeneration electrode 500 is a discharging liquid having an electricconductivity of not less than 50 μS/cm which does not form a hardlysoluble or insoluble compound through a reaction with ions removed fromthe ion exchanger 460. Such a discharging liquid, because of its lowelectric resistance, can reduce the power consumption in theregeneration section. Moreover the discharging liquid does not form aninsoluble compound (by-product) through a reaction with an impurity ion.In this regard, an insoluble compound, if formed, will adhere to thepartition 492 whereby the electric resistance between the regenerationelectrode 500 and the processing electrode 456 will be changed, makingit difficult to control the electrolysis current. Such a problem canthus be prevented.

[0199] After completion of the electrolytic processing, electricalconnections between the processing power source 484 and the processingelectrode 456, and between the power processing source 484 and thefeeding electrode 458 are shut off by means of the control box 482.Then, the rotation of the substrate holder 454 and the scroll movementof the electrode section 462 are stopped. Thereafter, the pivot arm 62is pivoted to transfer the electrolytic processed substrate W to thenext process.

[0200]FIGS. 22 and 23 show an electrolytic processing apparatus 450 aaccording to still another embodiment of the present invention. As withthe embodiment shown in FIGS. 20 and 21, the electrolytic processingapparatus 450 a includes a regeneration section on the processingelectrode side. The apparatus 450 a is provided with a regenerationsection 490 a including a processing electrode portion 504 composed ofthe processing electrode 456 and the same partition 492 as describedabove and a second partition 502 which are mounted on the both surfacesof the processing electrode 456, a regeneration electrode 500 disposedat a distance from the processing electrode 456, and a discharge portion494 a for flowing a discharging liquid therethrough, which is formedbetween the processing electrode portion 504 and the regenerationelectrode 500. The apparatus 450 a is also provided with a regenerationpower source 506. The processing electrode 456 is connected to thecathode of the processing power source 484 and to the anode of theregeneration power source 506; the regeneration electrode 500 isconnected to the cathode of the regeneration power source 506. Accordingto this embodiment, as with the above-described partition 492, an ionexchanger having the same type of ion-exchange group as the ionexchanger 460 to be regenerated, i.e. a cation exchanger, is used as thesecond partition 502. Further, the processing electrode 456 is disposedclose to the ion exchanger 460, thus close to a workpiece, with thepartition 492 interposed. The other construction is almost the same asthe embodiment shown in FIGS. 20 and 21. According to this embodiment, amesh electrode having numerous meshes as through-holes is used as theprocessing electrode 456. Ionic processing products (impurity ions)coming from the ion exchanger 460 pass through the numerous meshes(through-holes) of the processing electrode 456 and reach the dischargeportion 494 a.

[0201] By thus disposing the processing electrode 456 close to the ionexchanger 460, with the partition 492 interposed, and connecting theprocessing electrode 456 to the cathode of the processing power source484, the position at which the processing electrode 456 is disposed,which is close to the ion exchange 460, can be made the same electricpotential as the cathode of the processing power source 484. Thus, ascompared e.g. with the case shown in FIG. 8 in which the processingelectrode 232 is disposed at a distance from the ion exchanger and thusfrom a workpiece, the same potential as the cathode of the processingpower source 484 can be created at a closer position to a workpieceaccording to this embodiment. This can create a uniform electric field,enabling a stable processing. Furthermore, the closeness of theprocessing electrode 456 to the ion exchanger 460 makes it possible tocarry out removal of ionic processing products accumulated within theion exchanger 460 or regeneration of the ion exchanger 460 moreuniformly. In this regard, if the processing electrode 456 is distantfrom the ion exchanger 460, due to deposits present therebetween,accumulation of gas bubbles, etc., the electric resistances of internalmicro portions of the ion exchanger can change. This can affect theelectric current upon processing (regeneration), leading to variation ofthe electric field. Accordingly, when electrolytic processing of aworkpiece and regeneration of the ion exchanger are continued, there maybe a case in which an efficient regeneration of the ion exchanger oruniform regeneration of the ion exchanger can be made with difficulty,which may lead to difficulty in carrying out uniform processing of aworkpiece.

[0202] According to this embodiment, the processing electrode 456 isdisposed at a closer position to the ion exchanger 460 so as to createthe same potential at the closer position to the ion exchanger 460,thereby suppressing variation of the electric field and reducing theadverse effect of deposits and gas bubbles. Further, by connecting thefeeding electrode 458, the processing electrode 456 and the regenerationelectrode 500 of a lower potential than the processing electrode 456 inseries, regeneration of the ion exchanger 460 can be carried outsimultaneous with processing of a workpiece.

[0203] In order to carry out uniform processing/regeneration, it ispreferred that the surface of a workpiece W, the processing electrode456, the regeneration electrode 500 and the below-described intermediateelectrode 505 be parallel with one another. It is also desired that thethickness of the ion exchanger 460 be uniform.

[0204] When regenerating an ion exchanger (cation exchanger) 460 e.g. onthe processing electrode 456 side having the regeneration section 490 a,a regeneration voltage is applied between the processing electrode 456as an anode and a regeneration electrode 500 as a cathode via aregeneration power source 506. By thus forcibly passing an electriccurrent between the processing electrode 456 and the regenerationelectrode 500, the ionic processing products (impurity ions) accumulatedwithin the ion exchanger 460 are passed through the processing electrode456 and the partitions 492, 502, and moved into the discharge portion494 a. A processing power source 484 is generally expensive because ofits need for a CC (constant current) or CV (constant voltage) control.The regeneration power source 506, on the other hand, needs no suchcontrol, and therefore a less expensive electrode can be employed.

[0205] As described above, to the discharge portion 494 a of theregeneration section 490 a is supplied a discharging liquid having highelectric conductivity, e.g. not less than 50 μS/cm, which does not forma hardly soluble or insoluble compound through a reaction with ionsremoved from the ion exchanger 460, e.g. sulfuric acid with aconcentration of 1 wt % or higher. Though this embodiment employs as theprocessing electrode 456 an electrode connected to the cathode of theprocessing power source 484, it is also possible to use a so-calledfloating electrode not connected to a power source. Even with the use ofa floating electrode as the processing electrode, it is possible tocreate the same potential over the floating electrode surface. Accordingto this embodiment, the two partitions 492, 502 composed of ionexchangers are mounted on the both sides of the processing electrode456. Therefore, even if one of the partitions 492, 502 is broken, theother one can prevent the discharging liquid (usually an electrolyticsolution) from leaking toward the surface of the substrate W(workpiece).

[0206]FIG. 24A shows another processing electrode portion 504 a. Theprocessing electrode portion 504 a includes a mesh-shaped intermediateelectrode 505. The partition 492 is sandwiched between the processingelectrode 456 and the intermediate electrode 505. The intermediateelectrode 505 is connected to the anode of a drawing power source 508,and the processing electrode 456 is connected to the cathode of thedrawing power source 508. The processing electrode herein refers to anelectrode connected to the processing electrode of a processing powersource. Either the electrode 456 or the electrode 505 may be connectedto the processing electrode (cathode according to this embodiment) ofthe processing electrode. The electrode connected to the cathode of theprocessing power source becomes a processing electrode, and the otherelectrode becomes an intermediate electrode when it is positioned on theworkpiece side of the processing electrode, and a buffer electrode whenit is positioned on the discharge portion side of the processingelectrode. Further, according to this embodiment, the processingelectrode portion 504 a is supported on supports 510 disposed verticallyin the discharge portion 494 a.

[0207] By thus interposing the intermediate electrode 505 between aworkpiece and the processing electrode 456, it becomes possible to makethe electric potential constant at the surface of the intermediateelectrode which is at a closer distance to the workpiece than theprocessing electrode 456, thereby stabilizing the electric potential andthe electric field in the vicinity of the workpiece and stabilizing theprocessing efficiency. In this case, the voltage applied between theprocessing electrode 456 and the intermediate 505 is made smaller thanthe voltage applied between the workpiece and the processing electrode456.

[0208] Further, by supporting the processing electrode portion 504 a,i.e. the processing electrode 456, the intermediate electrode 505 andthe partition 492, on the supports 510, positioning and fixing of thepartition 492 can be made automatically via the aid of the stiffelectrodes 456, 505. This eliminates the need to provide a structure forholding the partition 492, and thus can simplify the construction.

[0209]FIG. 24B shows still another processing electrode portion 504 b.The electrode portion 504 b includes a buffer electrode 505 a betweenthe processing electrode 456 and the regeneration electrode 500 as anelectrode for adjusting the electric potential therebetween. In thiscase, a drawing electrode is not provided, and the partition 492 issandwiched between the processing electrode 456 and the buffer electrode505 a. The buffer electrode 505 a on the discharge portion 494 a side isa so-called floating electrode. The floating electrode 505 a has anelectric potential determined by a potential difference from thepotential of the workpiece surface or from the regeneration electrodesurface and other environmental factors, and can create the samepotential over the electrode surface. The use of such a buffer electrodecan therefore realize a uniform regeneration of the ion exchanger.

[0210]FIG. 25 shows another regeneration section 490 b. According tothis embodiment, the ion exchanger is composed of two groups of ionexchangers. The surface side first-group ion exchanger 460 is a laminateof a surface layer 460 a and a backside layer 460 b, and thesecond-group ion exchanger 492 is a three-layer laminate of a top layer492 a, an intermediate layer 492 b and a bottom layer 492 c. The totalion exchanger is thus of a five-layer laminated structure. Thesecond-group ion exchanger 492 also functions as a partition. Such alamination enhances the rigidity of the ion exchanger 460 and increasesthe ion-exchange capacity. The regeneration section 460 b is providedwith a mesh-shaped floating electrode 407, not connected to theprocessing power source, as an intermediate electrode.

[0211] The floating electrode portion 509, which is supported by thesupports 510, covers the top opening of a discharge portion 494 b thatis provided at the bottom an electrode 511 as a processing electrode andalso as a regeneration electrode. In the discharge portion 494 b, thereare also provide stirring blades 514 that rotate by the actuation ofmotors 512 and stir the discharging liquid in the discharge portion 494b. Further according to this embodiment, the discharging liquid fordischarging contaminants is supplied from a discharging liquid supplypipe 516 into the discharge portion 494 b, and the discharging liquid inthe discharge portion 494 b is discharged out from a discharging liquiddischarge pipe 518. The discharging liquid supply pipe 516 is so desiredthat a fresh discharging liquid is supplied close to the partition.

[0212] Further, though not figured, an additional mesh-shaped floatingelectrode may be disposed between the first-group ion exchanger 460 andthe second-group ion exchanger 492. Such an additional floatingelectrode can create the same potential at the closer position to theion exchanger 460, thereby suppressing variation of the electric fieldand reducing the adverse effect of deposits and gas bubbles.

[0213] By thus disposing the stirring blades 514 in the dischargeportion 494 b and forcibly stirring the discharging liquid in thedischarge portion 494 b by the stirring blades 514, gas bubbles(hydrogen gas bubbles in removal processing of copper) generated in thesurface of the processing/regeneration electrode 511 upon electrolyticprocessing can be prevented from adhering to the partitions 492, 502,and impeding formation of a uniform electric field and impeding theion-exchange reaction itself.

[0214]FIG. 26 shows a circulation system of the discharging liquid fordischarging contaminants, including the regeneration section 490 b ofFIG. 25. The circulation system includes the discharge portion 494 b anda circulation line 520 for holding the discharging liquid therein andcirculating the discharging liquid. In the circulation line 520, thereare provide a circulation pump 522 and a deaerator 524 for removing agas, which has been generated during electrolytic processing and takenin the discharging liquid, from the discharging liquid and supplying thedischarging liquid with a lowered dissolved gas content into thedischarge portion 494 b. Further, to the circulation line 520 isconnected a discharge line 528 which extends from a discharge tank 530,and a supply line 534 which extends from a supply tank 530 and has onits way a supply pump 532.

[0215] According to this embodiment, a deaerating film-type deaerationchamber is used as the deaerator 524, with which deaeration is effectedin the following manner: A pressure data as detected by a pressuresensor 536 is input to a pressure control circuit 538. Based on anoutput signal from the pressure control circuit 538, the degree ofopening of an open/close value 542, provided between a vacuum pump 540and the deaerating film-type deaeration chamber, is controlled so as tocontrol the pressure in the deaeration chamber 544 at a constant reducedpressure. The external pressure of a deaerating film 546, which isdisposed in the deaeration chamber 544 and constitutes part of thecirculation line 520, is thus reduced whereby a gas in the dischargingliquid flowing in the deaerating film 546 is removed.

[0216] By thus providing the circulation line 520, deaerating thedischarging liquid flowing through the circulation line 520 andsupplying the deaerated discharging liquid into the discharge portion494 b, it becomes possible to reuse the discharging liquid. Further, byconnecting the discharge line 528 and the supply line 534 to thecirculation line 520, it becomes possible to replace the dischargingliquid, which has lost the regenerating ability, with a freshdischarging liquid. The discharging liquid may be reused not bycirculation but batch-wise.

[0217]FIG. 27 is a plan view showing an electrolytic processingapparatus 334 according to still another embodiment of the presentinvention, FIG. 28 is a vertical sectional view of FIG. 27. As shown inFIGS. 27 and 28, the electrolytic processing apparatus 334 includes aarm 340 that can move vertically and make a reciprocating motion along ahorizontally plane, a substrate holder 342, supported at the free end ofthe arm 340, for attracting and holding the substrate W with its frontsurface facing downward (face-down), a moveable flame 344 connected tothe arm 340, a rectangular-shaped electrode section 346, and aprocessing power source 348 connected to the electrode section 346.According to this embodiment, the ion electrode section 346 is designedto have a diameter that is larger than that of the substrate W held bysubstrate holder 342.

[0218] As shown in FIGS. 27 and 28, a motor 350 for vertical movement ismounted on the upper portion of the moveable frame 344, and a ball screw352, extending vertically, is coupled to the motor 350 for verticalmovement. A base portion 340 a of the arm 340 is engaged with the bollscrew 350 so that the arm 340 moves up and down via a ball screw 352 bythe actuation of a motor 350 for vertical movement. The moveable frame344 is engaged with a boll screw 354, extending horizontally, so thatthe moveable frame 344 and the arm 340 make a reciprocating motion alonga horizontally plane by the actuation of a motor 356 for reciprocatingmotion

[0219] The substrate holder 342 is connected to a rotating motor 358provided at the free end of the arm 340, and allowed to rotate by theactuation of a motor 358. As described above, the arm 340 is adapted tomove vertically and make a reciprocating motion along a horizontallyplane, the substrate holder 342 is adapted to move vertically and make areciprocating motion along a horizontally plane integrated with the arm340.

[0220] The hollow motor 360 is disposed below the electrode section 346.A drive end 364 is formed at the upper end portion of the main shaft 362of the hollow motor 360 and arranged eccentrically position to thecenter of the main shaft 362. The electrode section 346 is connected tothe drive end 364 via a bearing (not shown) at the center portionthereof. Three or more of rotation-prevention mechanisms are provided inthe circumferential direction between the electrode section 346 and thehollow motor 360.

[0221]FIG. 29A is a plan view showing the rotation-prevention mechanismsof this embodiment, and FIG. 29B is a cross-sectional view taken alongthe line A-A of FIG. 29A. As shown in FIGS. 29A and 29B, three or more(four in FIG. 29A) of rotation-prevention mechanisms 366 are provided inthe circumferential direction between the electrode section 346 and thehollow motor 360. As shown in FIG. 29B, a plurality of depressions 368,370 are formed at equal intervals in the circumferential direction atthe corresponding positions in the upper surface of the hollow motor 360and in the lower surface of the electrode section 346. Bearings 372, 374are fixed in each depression 368, 370, respectively. A connecting member380, which has two shafts 376, 378 that are eccentric to each other byeccentricity “e”, is coupled to each pair of the bearings 372, 374 byinserting the respective ends of the shafts 376, 378 into the bearings372, 374. Further, a drive end 364, formed at the upper end portion ofthe main shaft 362 of the hollow motor 360 and arranged eccentricallyposition to the center of the main shaft 362, is rotatably connected,via a bearing (not shown), to a lower central portion of the electrodesection 346. The eccentricity is also “e”. Accordingly, the electrodesection 346 is allowed to make a scroll movement (translational rotationmovement), along a circle with radius “e”.

[0222] A plurality of electrode plates 382 are disposed in parallel,spaced at a given pitch, in the upper surface of the electrode section346, and the cathode and the anode of the processing power source 348are alternately connected to the electrode plates 382, so that theelectrode plates 382 connected to the cathode becomes the processingelectrodes 200, adversely, the electrode plates 382 connected to theanode becomes the feeding electrodes 201. The processing electrodes 200and the feeding electrodes 201 are thus disposed alternately. Thesurface each of the processing electrodes 200 and the feeding electrodes201 is covered with ion exchanger, respectively.

[0223] According to this embodiment, as with the above-describedembodiments, a regeneration section is provided on the processingelectrode side. FIGS. 30A to 30C show the electrode plate 382 which isconnected to the cathode of the processing power source 348 and becomesa processing electrode 600, and FIG. 31 shows a distribution system ofthe discharging liquid for discharging contaminants, including theregeneration section. As shown in FIGS. 30A to 30C, in the upper portionof the long processing electrode (electrode plate) 600, extendinglinearly and connected to the cathode of the processing power source348, there is provided a cut-away portion 600 a which has been formed bycutting away part of the electrode 600 while leaving the both endportions. An ion exchanger 602, having the shape of the letter “U” incross-section, is mounted fitly on the processing electrode 600 so thatthe ion exchanger 602 covers the cut-away portion 600 a, whereby aclosed discharging liquid flow passage 604 is formed between thecut-away portion 600 a and the ion exchanger 602. The regenerationsection 606, having the discharging liquid flow passage 604, is thusconstructed. Regeneration of the ion exchanger 602 is effected byutilizing the ion exchanger itself as a partition and, in the samemanner as described above, by flowing through the discharging liquidflow passage 604 a discharging liquid having an electric conductivity ofe.g. not less than 50 μS/cm which does not form a hardly soluble orinsoluble compound through a reaction with ions removed from the ionexchanger 602 mounted on the workpiece side surface of the processingelectrode 600.

[0224] At the both ends of the processing electrode 600, there areformed through-holes 600 b, 600 c, each opening at one end of the endsurface of the processing electrode 600 and at one end of the cut-awayportion 600 a. One through-hole 600 b is connected to a liquid supplypipe 612 which extends from a supply tank 608 and has on its way apressure-supply pump 610, and the other through-hole 600 c is connectedto a liquid discharge pipe 616 which has on its way a pressureregulation valve 614. An open flow line is thus constructed in which bythe actuation of the pressure-supply pump 610, the discharging liquid inthe supply tank 608 is pressure-supplied into the discharging liquidflow passage 604 of the regeneration section 606, and the dischargingliquid flows in one direction in the discharging liquid flow passage 604and flows out of the system.

[0225] According to this embodiment, a substrate W is held by thesubstrate holder 342, and the substrate holder 342 is lowered so as tobring the substrate W close to or in contact with the ion exchangermounted on the surface of the electrode section 346. While rotating thesubstrate holder 342 and allowing the electrode section 346 to make ascroll movement and a reciprocating movement, a voltage is appliedbetween the processing electrode 600 and the feeding electrode 601 and,at the same, a processing liquid such as pure water is supplied to thesurface of the substrate W, thereby carrying out electrolyticprocessing. Processing proceeds in the region in which the workpiece andthe ion exchanger 302 covering the processing electrode 600 are closedto or in contact with each other. During the electrolytic processing,while regulating the pressure on the upstream side of the pressureregulation valve 614 by the valve 614, the discharging liquid ispressure-supplied into the discharging liquid flow passage 604 of theregeneration section 606, thereby allowing reaction products taken inthe ion exchanger 602 to flow into the discharging liquid. During theprocessing, gas bubbles may be generated by electrolysis of water in thedischarging liquid in the discharging liquid flow passage 604. If thepressure regulation valve 614 is completely closed during theprocessing, gas bubbles or gasses may remain within the dischargingliquid flow passage 604 to lower the processing efficiency and, as thecase may be, the ion exchanger 602 can be broken due to the expansion ofthe discharging liquid. Accordingly, it is desired to continuouslysupply the discharging liquid during processing at such a flow rate thatthe gas bubbles or gasses generated do not affect the processing, anddischarge the discharging liquid, together with the gas bubbles, fromthe discharging liquid flow passage 604.

[0226] When gas bubbles or gasses are generated in a large amount, it isnecessary to supply the discharging liquid at a high flow rate.Therefore, there may be a case where the discharging liquid isdischarged as waste while the liquid still has a sufficient processingcapacity. Accordingly, it is desired to adjust the concentration of thedischarging liquid so that the flow rate meets the processing capacitynecessary per unit of time. The amount of waste liquid can be reduced bycirculating the discharging liquid during processing, as describedbelow.

[0227]FIG. 32 shows another distribution system of the dischargingliquid for discharging contaminants, including the regeneration section606 shown in FIGS. 30A to 30C and FIG. 31. According to this embodiment,the through-holes 600 b, 600 c provided at the both ends of theprocessing electrode 600 are connected through the circulation line 620.Between the pressure-supply pump 610 and the pressure regulation valve614, which are provided in the circulation line 620 on both sides of theprocessing electrode 600, there are disposed a discharging liquidregeneration section 622 provided with a liquid regeneration electrodefor regenerating the discharging liquid, and a deaerator 624 forremoving gas bubbles or gasses taken in the discharging liquid. Inelectrolytic processing of e.g. copper, copper dissolved in thedischarging liquid is precipitated in the discharging liquidregeneration section 622. A closed circuit is thus formed in which bythe actuation of the pressure-supply pump 610, the discharging liquid ispressure-supplied to the regeneration section 606, and is then sent tothe deaerator 624 where the liquid is deaerated, and the deaerateddischarging liquid is sent to the discharging liquid regenerationsection 622 where the liquid is regenerated, and the regenerateddischarging liquid is returned to the pressure-supply pump 610. Thedischarging liquid can thus be reused.

[0228] Insulating sections for preventing a short-circuit between theprocessing electrode 600 and the liquid regeneration electrode providedin the discharging liquid regeneration section 622 are provided beforeand after the regeneration section 622, whereby regeneration of thedischarging liquid by the regeneration section 622 can be carried outefficiently while preventing a short circuit.

[0229]FIGS. 33 and 34 show an electrode section having still anotherregeneration section 606 a. This embodiment employs, as the ionexchanger 602 that forms the discharging liquid flow passage 604 betweenit and the processing electrode 600, a two-layer laminate consisting ofa surface layer 602 a composed of a thin film-type ion exchanger havinga surface smoothness and flexibility and a backside layer 602 b composedof an elastic ion exchanger having a large ion-exchange capacity.Further, a support 626 for supporting the ion exchanger 602 in a flatstate is provided in the discharging liquid flow passage 604.Through-holes 626 a are provided at certain positions in the support626. According to this embodiment, the ion exchanger of the surfacelayer 602 a serves as a partition.

[0230] Such an ion exchanger 602 of two-layer laminate structure,because of the backside layer 602 b having a large ion-exchangecapacity, has an increased total ion-exchange capacity. Further, becauseof the elasticity, the ion exchanger 602 can be prevented from beingdamaged even when an excessive pressure is applied thereto inelectrolytic processing. As the surface layer 602 a, an ion exchangerwhich is permeable to ions, but not permeable to a liquid, may be usedwhen an electrolytic solution is used as the discharging liquid thatflows through the discharging liquid flow passage 604. When thebelow-described ion-exchange liquid is used as the discharging liquid,the surface layer 602 may permit permeation therethrough of waterinsofar as an ion exchanger in the discharging liquid does not leaktherethrough. The provision of the support 626 ensures the formation ofthe discharging liquid flow passage 604 and enables lamination of theion exchanger on the support.

[0231]FIG. 35 shows a variation of the regeneration section shown inFIGS. 33 and 34. According to this embodiment, a partition 626 bcomposed of an ion exchanger in the form of a membrane is mounted to theback surface of the ion exchanger 602 of two-layer structure, and theion exchanger 602 having the partition 626 b is supported by a support628 provided in the discharging liquid flow passage 604. The provisionof the support 628 makes it possible to use a thin film-type ionexchanger as the ion exchanger 602, and allow such a film-type ionexchanger 602 to contact the workpiece W flexibly. The flexibility isrequired to respond to variations of the to-be-processed surface of theworkpiece due to the size of the workpiece, the relative movementbetween the workpiece and the ion exchanger, etc.

[0232] The support 628 has a number of through-holes 628 a. The support628 can hold the ion exchanger 602 in a tense state. Owing to thetensity and the elasticity of the ion exchanger 602, the workpiece Wsuch as a substrate can contact the surface of the ion exchanger 602over the entire surface of the workpiece. According to the embodiment ofFIG. 35, two layers of the surface layer 602 a and the partition 626 bfunction as a partition. Should one of the layers be broken, thedischarging liquid can be kept away from leaking into the workpieceside.

[0233] When the ion-exchange capacity of the ion exchanger 602 reachesits limit, the ionic processing products are taken in the dischargingliquid flowing through the discharging liquid flow passage 604, wherebythe ion exchanger 602 is regenerated. The regeneration can eliminate orat least lessen the time and labor for exchange of the ion exchanger 602covering the surface of the processing electrode 600. According to thisembodiment, ion exchangers are used for the surface layer 602 a and thebackside layer 602 b because they meet the requirements ofelectrochemical inactivity, elasticity and permeability to ions.Provided these requirements are met, other materials may be employed.

[0234] When the support 628 is formed of an electrochemically inactiveinsulating material, e.g. Teflon, which is different from the materialof the processing electrode 600, feeding of electricity to the workpieceis made through the ion exchanger, whereby processing products can beefficiently taken in the discharging liquid. Further, it is possible toform the partition 626 b of such an ion exchanger that allows pure waterto flow on the partition, that is, along the backside layer 602 b, andallows the discharging liquid to flow below the partition, that is,through the discharging liquid flow passage 604. This makes it possibleto keep the discharging liquid, which is generally harmful, away fromthe processing surface and, if the ion exchanger, providing theprocessing surface, is broken, prevent the discharging liquid fromflowing through the partition 626 b into the workpiece side. As thesurface layer 602 a, an ion exchanger which is permeable to ions, butnot permeable to a liquid, may be used when an electrolytic solution isused as the discharging liquid that flows through the discharging liquidflow passage 604. When the below-described ion-exchange liquid is usedas the discharging liquid, the surface layer 602 a may permit permeationtherethrough of water insofar as an ion exchanger in the dischargingliquid does not leak therethrough.

[0235]FIGS. 36 through 38 show still another electrode section of anelectrolytic processing apparatus. These Figures show a unit, includinga pair of a processing electrode and a feeding electrode, of the entireelectrode section. The actual or entire electrode section, as shown e.g.in FIG. 27, is generally square and comprises a plurality of unitsdisposed in parallel. The entire electrode section, when used inelectrolytic processing, is allowed to rotate or make a scroll movement.According to this embodiment, an ion exchanger on the processingelectrode side is regenerated, and pure water is employed as aprocessing liquid.

[0236] The electrode section includes an electrode plate 640. On theupper surface of the electrode plate 640, a long processing electrode642 to be connected to the cathode of a processing power source and along feeding electrode 644 to be connected to the anode of theprocessing power source are disposed is parallel. On both sides of theprocessing electrode 642, a pair of long pure water jet nozzles 646 isdisposed.

[0237] A support 648, which opens downwardly and has a horseshoe shapein cross-section, and extends over almost the full length of theprocessing electrode 642, is mounted on the upper surface of theprocessing electrode 642. A discharging liquid flow passage 650,extending over almost the full length of the processing electrode 642,is formed by the depressed portion of the support 648. The support 648has in the upper portion openings 648 a spaced at a given pitch in thelong direction. The upper surface of the support 648 is covered with anion exchanger 652 composed of a surface layer 652 a and a three-layerlaminate 652 b. The surface layer 652 a of the ion exchanger 652 servesas a partition. Vertically-extending liquid supply passages 642 a areprovided at certain positions in the processing electrode 642. Theliquid supply passages 642 a connected to a discharging liquidintroduction/discharge passage 640 a provided within the electrode plate640. A discharging liquid introduction plug 654 which is connected to aliquid supply pipe and discharging liquid discharge plugs 656 which areconnected to liquid discharge pipes are connected to the dischargingliquid introduction/discharge passage 640 a.

[0238] The discharging liquid is introduced into the discharging liquidflow passage 650 via the liquid supply pipe connected to the dischargingliquid introduction plug 654. The discharging liquid introduced into thedischarging liquid flow passage 650 flows through the passage 650 and,at the same time, partly passes through the openings 648 a and reachesthe ion exchanger 652, and is discharged from the liquid discharge pipesconnected to the discharging liquid discharge plugs 656.

[0239] Positioned above the electrode plate 640, through-holes 642 b,each opening at the end surface of the electrode plate 640 and at thedischarging liquid flow passage 650, are provided at the both ends ofthe processing electrode 642. Discharging liquid discharge plugs660,which are connected to e.g. the discharging liquid discharge pipes616 shown in FIGS. 30A to 30C and FIG. 31, are connected to thethrough-holes 642 b, respectively. The above construction makes itpossible to continuously supply the discharging liquid into thedischarging liquid flow passage 650 at such a flow rate that gas bubblesor gasses generated during processing do not affect the processing, anddischarge the discharging liquid, together with the gas bubbles orgasses, from the discharging liquid flow passage 650.

[0240] On the other hand, in the interior of the feeding electrode 644,there is formed a pure water flow passage 644 a that extends over thefull length of the feeding electrode 644. The upper surface of thefeeding electrode 644 is covered with an ion exchanger 662 composed of asurface layer 662 a and a three-layer laminate 662 b. Through-holes 644b, extending from the pure water flow passage 644 a and reaching theupper surface of the feeding electrode 644, are provided at certainpositions in the feeding electrode 644. Further, though not figured,pure water passage, connecting to the pure water flow passage 644 a, isprovided within the electrode plate 640 and in the feeding electrode644. Pure water introduction plugs 664, which are connected to purewater supply pipes, are connected to the pure water passage.

[0241] Pure water is introduced into the pure water flow passage 644 avia the pure water supply pipes connected to the pure water introductionplugs 664. The pure water introduced into the pure water flow passage644 a flows through the pure water flow passage 644 a and, at the sametime, partly passes through the through-holes 644 b, reaches the ionexchanger 662 and leaks out of the surface of the ion exchanger 662.

[0242] In the interior of each pure water jet nozzle 646, there isprovided a pure water flow passage 646 a which extends over the fulllength of the water jet nozzle 646. Pure water jet orifices 646 b, whichconnect to the pure water flow passage 646 a and jet pure water towardthe ion exchanger 652, are provided in the pure water jet nozzle 646 ata given pitch in the long direction. By supplying pure water into thepure water flow passage 646 a, pure water is jetted from the pure waterjet orifices 646 b mainly toward the upper surface of the ion exchanger652 covering the upper surface of the processing electrode 642.

[0243] The processing electrode 642 with the ion exchanger 652 mountedthereon and the pair of pure water jet nozzles 646 disposed on bothsides of the processing electrode 642 are integrated by fastening taps672 from the outside of the pure water nozzles 646 to tap bars 670disposed on both sides of the lower portion of the processing electrode642. The surface layer 652 a of the ion exchanger 652 is disposed suchthat it covers almost the entire surface of the processing electrode642. The side portion of the surface layer 652 a is positioned betweenthe processing electrode 642 and the pure water jet nozzle 646. Further,the processing electrode 642 and the ion exchanger surface layer 652 aare tightened, with an O-ring 674 being interposed therebetween, wherebythe discharging liquid flow passage 650 between the processing electrode642 and the ion exchanger surface layer (partition) 652 a is madewatertight.

[0244] The thus integrated processing electrode 642 and pure water jetnozzles 646 are sandwiched between a pair of insert plates 676 and fixedto the electrode plate 640. On the other hand, the feeding electrode644, with its surface covered with the surface layer 662 a of the ionexchanger 662, is sandwiched between a pair of holding plates 678 andfixed to the electrode plate 640.

[0245] According to this embodiment, while allowing the ion exchanger652, covering the surface of the processing electrode 642, and the ionexchanger 662, covering the surface of the feeding electrode 644, to beclosed to or in contact with a workpiece and applying a voltage betweenthe processing electrode 642 and the feeding electrode 644, pure wateris supplied to the surface of the ion exchanger 652 of the processingelectrode 642 and to the surface of the ion exchanger 662 of the feedingelectrode 644 and, at the same time, the discharging liquid iscontinuously supplied into the discharging liquid flow passage 650 atsuch a flow rate that gas bubbles or gasses generated during processingdo not affect the processing to thereby fill the discharging liquid flowpassage 650 of the processing electrode 642 with the discharging liquidand discharge the discharging liquid, together with the gas bubbles, outof the passage 650. Processing of the workpiece and regeneration of theion exchanger 652, covering the surface of the processing electrode 642,can thus be carried out simultaneously.

[0246] Though the above-described embodiments use as the dischargingliquid an electrolytic solution having an electric conductivity of e.g.not less than 50 μS/cm, it is also possible to use as the dischargingliquid a liquid containing an ion-exchange group. Examples of thedischarging liquid containing an ion-exchange group may include an ionexchanger which itself has liquidity and a liquid obtained bypulverizing an ion exchanger having a large ion-exchange capacity, andmixing the pulverized product with a liquid such as pure water.

[0247] According to the present invention, as described hereinabove,regeneration of an ion exchanger can be carried out easily and quicklythrough an electrochemical section and in parallel with electrolyticprocessing. This eliminates the need to stop the processing for exchangeof ion exchanger and can increase the throughput. Further, the presentinvention can minimize contamination of the generated ion exchanger witha chemical liquid and minimize a load upon cleaning of the regeneratedion exchanger, and can eliminate the need to separately provide aregeneration section and reduce the installation space.

[0248] Although certain preferred embodiments of the present inventionhave been shown and described in detail, it should be understood thatvarious changes and modifications may be made therein without departingfrom the scope of the appended claims.

[0249] Industrial Applicability

[0250] The present invention relates to a method and device forregenerating an ion exchanger which, in electrolytic processing forprocessing an electrically conductive material on the surface of asubstrate such as a semiconductor wafer or removing impurities adheringto the substrate surface, can electrochemically remove a metal or otherions taken in an ion exchanger used in the electrolytic processing,thereby regenerating the ion exchanger.

1. A method for regenerating an ion exchanger for use in electrolyticprocessing, comprising: providing a pair of electrodes and an ionexchanger to be regenerated disposed between the electrodes; andapplying a voltage between the electrodes while supplying a liquidtherebetween, thereby regenerating the ion exchanger.
 2. The methodaccording to claim 1, wherein the liquid is ultrapure water, pure water,a liquid having an electric conductivity of not more than 500 μS/cm oran electrolytic solution.
 3. The method according to claim 1, wherein anion exchanger for regeneration is disposed between the ion exchanger tobe regenerated and at least one of the electrodes.
 4. The methodaccording to claim 3, wherein the ion exchanger for regeneration has anion-exchange group of the same polarity as the ion-exchange group of theion exchanger to be regenerated.
 5. The method according to claim 4,wherein the electrode disposed on the side of the ion exchanger to beregenerated is an anode when the ion exchanger to be regenerated and theion exchanger for regeneration are cation exchangers, and a cathode whenthe both ion exchangers are anion exchangers.
 6. A device forregenerating an ion exchanger that is disposed on an electrode for usein electrolytic processing, comprising: a regeneration section includinga regeneration electrode; a regeneration power source for applying avoltage between the electrode and the regeneration electrode; and aliquid supply section for supplying a liquid between the electrode andthe regeneration electrode; wherein the ion exchanger to be regeneratedis disposed between the electrode and the regeneration electrode.
 7. Thedevice according to claim 6, wherein the liquid is ultrapure water, purewater, a liquid having an electric conductivity of not more than 500μS/cm or an electrolytic solution.
 8. The device according to claim 6,further comprising an ion exchanger for regeneration disposed betweenthe ion exchanger to be regenerated and the regeneration electrode. 9.The device according to claim 8, wherein the ion exchanger forregeneration has an ion-exchange group of the same polarity as theion-exchange group of the ion exchanger to be regenerated.
 10. Thedevice according to claim 9, wherein the electrode disposed on the sideof the ion exchanger to be regenerated is an anode when the ionexchanger to be regenerated and the ion exchanger for regeneration arecation exchangers, and a cathode when the both ion exchangers are anionexchangers.
 11. The device according to claim 6, wherein at least one ofthe ion exchanger to be regenerated and the ion exchanger forregeneration is a laminate configured by a plurality of ion-exchangematerials.
 12. The device according to claim 6 further comprising amonitor for monitoring the electrolysis current and time, and/or thequantity of electricity when the voltage is applied between theelectrode and the regeneration electrode.
 13. A method for regeneratinga contaminated ion exchanger, comprising: providing a regenerationelectrode and a counter electrode, a partition disposed between theregeneration electrode and the counter electrode, and an ion exchangerto be regenerated disposed between the counter electrode and thepartition; and applying a voltage between the regeneration electrode andthe counter electrode while supplying a liquid between the partition andthe regeneration electrode and also supplying a liquid between thepartition and the counter electrode.
 14. The method according to claim13, wherein the partition comprises an ion exchanger.
 15. The methodaccording to claim 14, wherein the partition is a cation exchanger whenthe ion exchanger to be regenerated is a cation exchanger, and an anionexchanger when the ion exchanger to be regenerated is an anionexchanger.
 16. The method according to claim 13, wherein theregeneration electrode is a cathode when the ion exchanger to beregenerated is a cation exchanger, and an anode when the ion exchangerto be regenerated is an anion exchanger.
 17. The method according toclaim 13, wherein the liquid supplied between the partition and thecounter electrode is ultrapure water, pure water or a liquid having anelectric conductivity of not more than 500 μS/cm.
 18. The methodaccording to claim 13, wherein the liquid supplied between the partitionand the regeneration electrode is a liquid having an electricconductivity of not less than 50 μS/cm which does not form a hardlysoluble or insoluble compound through a reaction with an ion which isremoved from the ion exchanger to be regenerated.
 19. A device forregenerating an ion exchanger, comprising: a regeneration electrode anda counter electrode disposed opposite to each other; a partitiondisposed between the regeneration electrode and the counter electrode; apower source for applying a voltage between the regeneration electrodeand the counter electrode; and a liquid supply section for supplying aliquid between the partition and the regeneration electrode and/orbetween the partition and the counter electrode; wherein an ionexchanger to be regenerated is disposed between the partition and theregeneration electrode.
 20. The device according to claim 19, whereinthe partition comprises an ion exchanger.
 21. The device according toclaim 20, wherein the partition is a cation exchanger when the ionexchanger to be regenerated is a cation exchanger, and an anionexchanger when the ion exchanger to be regenerated is an anionexchanger.
 22. The device according to claim 19, wherein theregeneration electrode is a cathode when the ion exchanger to beregenerated is a cation exchanger, and an anode when the ion exchangerto be regenerated is an anion exchanger.
 23. The device according toclaim 19, wherein the liquid supplied between the partition and thecounter electrode is ultrapure water, pure water or a liquid having anelectric conductivity of not more than 500 μS/cm.
 24. The deviceaccording to claim 19, wherein the liquid supplied between the partitionand the regeneration electrode is a liquid having an electricconductivity of not less than 50 μS/cm which does not form a hardlysoluble or insoluble compound through a reaction with an ion which isremoved from the ion exchanger to be regenerated.
 25. The deviceaccording to claim 19, further comprising a monitor for monitoring theelectrolysis current and time, and/or the quantity of electricity whenthe voltage is applied between the electrode plate and the regenerationelectrode.
 26. An electrolytic processing apparatus, comprising: aprocessing electrode which can come close to or into contact with aworkpiece; a feeding electrode for feeding electricity to the workpiece;an ion exchanger provided on a workpiece side surface of at least one ofthe processing electrode and the feeding electrode; a regenerationsection provided between the ion exchanger and said at least one of theprocessing electrode and the feeding electrode, provided with the ionexchanger; a processing power source for applying a processing voltagebetween the processing electrode and the feeding electrode; and aprocessing liquid supply section for supplying a processing liquid forelectrolytic processing to between the workpiece and said at least oneof the processing electrode and the feeding electrode, in which the ionexchanger is present.
 27. The electrolytic processing apparatusaccording to claim 26, wherein the regeneration section, comprises: apartition disposed close to or in contact with the ion exchanger; adischarge portion formed between the partition and at least one of theprocessing electrode and the feeding electrode; and a discharging liquidsupply section for supplying a discharging liquid to the dischargeportion, for discharging contaminants contained in the ion exchanger.28. The electrolytic processing apparatus according to claim 27, whereinthe partition comprises an ion exchanger.
 29. The electrolyticprocessing apparatus according to claim 28, wherein the partition is acation exchanger when the ion exchanger provided on the workpiece sidesurface of at least one of the processing electrode and the feedingelectrode is a cation exchanger, and an anion exchanger when the ionexchanger provided on the workpiece side surface of at least one of theprocessing electrode and the feeding electrode is an anion exchanger.30. The electrolytic processing apparatus according to claim 26, whereinthe processing liquid is ultrapure water, pure water or liquid having anelectric conductivity of not more than 500 μS/cm.
 31. The electrolyticprocessing apparatus according to claim 27, wherein the dischargingliquid is a liquid having an electric conductivity of not less than 50μS/cm which does not form a hardly soluble or insoluble compound througha reaction with an ion which is removed from the ion exchanger providedon the workpiece side surface of at least one of the processingelectrode and the feeding electrode.
 32. An electrolytic processingapparatus, comprising: a processing electrode which can come close to orinto contact with a workpiece; a feeding electrode for feedingelectricity to the workpiece; an ion exchanger provided on a workpieceside surface of at least one of the processing electrode and the feedingelectrode; a regeneration section including a regeneration electrode anda discharge portion for flowing a discharging liquid therethrough, saiddischarge portion being formed between the regeneration electrode andsaid at least one of the processing electrode and the feeding electrode,provided with the ion exchanger; a processing power source for applyinga processing voltage between the processing electrode and the feedingelectrode; and a processing liquid supply section for supplying aprocessing liquid for electrolytic processing to between the workpieceand said at least one of the processing electrode and the feedingelectrode, in which the ion exchanger is present.
 33. The electrolyticprocessing apparatus according to claim 32, further comprising apartition between the ion exchanger and said at least one of theprocessing electrode and the feeding electrode, provided with the ionexchanger, and/or between the regeneration electrode and said one of theprocessing electrode and the feeding electrode.
 34. The electrolyticprocessing apparatus according to claim 32, wherein the partition isprovided on both sides of said at least one of the processing electrodeand the feeding electrode, provided with the ion exchanger.
 35. Theelectrolytic processing apparatus according to claim 33, wherein said atleast one of the processing electrode and the feeding electrode,provided with the ion exchanger, is in contact with the partition and issupported and fixed on a support.
 36. The electrolytic processingapparatus according to claim 32, wherein said at least one of theprocessing electrode and the feeding electrode, provided with the ionexchanger, has a through-hole for passing therethrough the dischargingliquid or the processing liquid.
 37. The electrolytic processingapparatus according to claim 32, further comprising an intermediateelectrode between the workpiece and said at least one of the processingelectrode and the feeding electrode, provided with the ion exchanger.38. The electrolytic processing apparatus according to claim 37, whereinthe intermediate electrode and said one of the processing electrode andthe feeding electrode, provided with the ion exchanger are connected toan intermediate power source.
 39. The electrolytic processing apparatusaccording to claim 38, wherein the intermediate electrode is a floatingelectrode that is not connected to a power source.
 40. The electrolyticprocessing apparatus according to claim 37, wherein the intermediateelectrode has a through-hole for passing therethrough the dischargingliquid or the processing liquid.
 41. The electrolytic processingapparatus according to claim 37, wherein the intermediate electrode islaminated with an ion exchanger or a partition.
 42. The electrolyticprocessing apparatus according to claim 32, wherein the dischargeportion is provided with a stirring means for forcibly stirring thedischarging liquid in the discharge portion.
 43. The electrolyticprocessing apparatus according to claim 32, further comprising adeaerator for deaerating the discharging liquid.
 44. An electrolyticprocessing method, comprising: providing a processing electrode, afeeding electrode, an ion exchanger provided on a workpiece side surfaceof at least one of the processing electrode and the feeding electrode,and a regeneration section formed between the ion exchanger and said atleast one of the processing electrode and the feeding electrode;allowing the processing electrode to be closed to or in contact with theworkpiece while feeding electricity from the feeding electrode to theworkpiece; supplying a processing liquid for electrolytic processing tobetween the workpiece and said at least one of the processing electrodeand the feeding electrode, in which the ion exchanger is present; andapplying a processing voltage between the processing electrode and thefeeding electrode, thereby carrying out electrolytic processing of theworkpiece by the processing electrode and regeneration of the ionexchanger by the regeneration section simultaneously.
 45. Theelectrolytic processing method according to claim 44, wherein theregeneration of the ion exchanger by the regeneration section is carriedout by passing impurity ions in the ion exchanger through a partitionand introducing the impurity ions into a discharge portion, anddischarging the impurity ions out of the system by the flow of adischarging liquid for discharging contaminants supplied into thedischarge portion.
 46. The electrolytic processing method according toclaim 45, wherein the partition comprises an ion exchanger.
 47. Theelectrolytic processing method according to claim 46, wherein thepartition is a cation exchanger when the ion exchanger provided on theworkpiece side surface of at least one of the processing electrode andthe feeding electrode is a cation exchanger, and an anion exchanger whenthe ion exchanger provided on the workpiece side surface of at least oneof the processing electrode and the feeding electrode is an anionexchanger.
 48. The electrolytic processing method according to claim 44,wherein the processing liquid is ultrapure water, pure water or liquidhaving an electric conductivity of not more than 500 μS/cm.
 49. Theelectrolytic processing method according to claim 44, wherein thedischarging liquid is a liquid having an electric conductivity of notless than 50 μS/cm which does not form a hardly soluble or insolublecompound through a reaction with an ion which is removed from the ionexchanger provided on the workpiece side surface of at least one of theprocessing electrode and the feeding electrode.
 50. An electrolyticprocessing apparatus, comprising: a processing electrode which can comeclose to or into contact with a workpiece; a feeding electrode forfeeding electricity to the workpiece; an ion exchanger provided on aworkpiece side surface of at least one of the processing electrode andthe feeding electrode; a discharging liquid flow passage, formed betweenthe ion exchanger and said at least one of the processing electrode andthe feeding electrode, provided with the ion exchanger, for flowingtherethrough a discharging liquid for discharging contaminants containedin the ion exchanger; a processing power source for applying aprocessing voltage between the processing electrode and the feedingelectrode; and a processing liquid supply section for supplying aprocessing liquid for electrolytic processing to between the workpieceand said at least one of the processing electrode and the feedingelectrode, in which the ion exchanger is present.
 51. The electrolyticprocessing apparatus according to claim 50, wherein a support forsupporting the ion exchanger in a flat state is provided in thedischarging liquid flow passage.
 52. The electrolytic processingapparatus according to claim 50, wherein the ion exchanger is amulti-layer laminate of two or more layers including a front surfacelayer composed of an ion exchanger in the form of a film and anintermediate or back surface layer composed of an elastic ion exchangerhaving a large ion-exchange capacity.
 53. The electrolytic processingapparatus according to claim 50, wherein the discharging liquid has anelectric conductivity of not less than 50 μS/cm.
 54. The electrolyticprocessing apparatus according to claim 50, wherein a partition isdisposed, close to or in contact with the ion exchanger, in thedischarging liquid flow passage.
 55. The electrolytic processingapparatus according to claim 54, wherein the partition comprises an ionexchanger.
 56. The electrolytic processing apparatus according to claim54, wherein the partition has a through-hole.
 57. The electrolyticprocessing apparatus according to claim 50, further comprising adischarging liquid regeneration section for regenerating the dischargingliquid which has flowed through the discharging liquid flow passage andflowed out of the flow passage.
 58. The electrolytic processingapparatus according to claim 57, wherein the discharging liquidregeneration section is provided with a liquid regeneration electrodewhich is electrically separated from the discharging liquid to beregenerated.
 59. The electrolytic processing apparatus according toclaim 58, wherein the discharging liquid regeneration section isprovided in a circulation line connecting the inlet and the outlet ofthe discharging liquid passage, and the circulation line is providedwith a deaerator.
 60. An electrolytic processing apparatus, comprising:a processing electrode which can come close to or into contact with aworkpiece; a feeding electrode for feeding electricity to the workpiece;an ion exchanger provided on a workpiece side surface of at least one ofthe processing electrode and the feeding electrode; a discharging liquidflow passage, formed between the ion exchanger and said at least one ofthe processing electrode and the feeding electrode, provided with theion exchanger, for flowing therethrough a discharging liquid containingan ion-exchange group for discharging contaminants; a processing powersource for applying a processing voltage between the processingelectrode and the feeding electrode; and a processing liquid supplysection for supplying a processing liquid for electrolytic processing tobetween the workpiece and said at least one of the processing electrodeand the feeding electrode, in which the ion exchanger is present.
 61. Anelectrolytic processing method comprising: providing a processingelectrode, a feeding electrode and an ion exchanger provided on aworkpiece side surface of at least one of the processing electrode andthe feeding electrode; allowing the processing electrode to be close toor in contact with a workpiece while feeding electricity from thefeeding electrode to the workpiece; and applying a processing voltagebetween the processing electrode and the feeding electrode whilesupplying a discharging liquid containing an ion-exchange group fordischarging contaminants into a discharging liquid flow passage formedbetween the ion exchanger and said at least one of the processingelectrode and the feeding electrode, provided with the ion exchanger,and also supplying a processing liquid for electric processing tobetween the workpiece and said at least one of the processing electrodeand the feeding electrode, in which the ion exchanger is present,thereby carrying out processing of the workpiece.